Implantable layers and methods for altering one or more properties of implantable layers for use with fastening instruments

ABSTRACT

A method is disclosed for changing the spring rate of an implantable layer for use with a surgical instrument which includes the steps of obtaining an implantable layer having a first spring rate, wherein the implantable layer is at least partially comprised of a material having a glass transition temperature and a melting temperature, heating the implantable layer to a temperature higher than the glass transition temperature and lower than the melting temperature, deforming the implantable layer to change the first spring rate to a second spring rate, wherein the second spring rate is different than the first spring rate, allowing the implantable layer to cool below the glass transition temperature, and releasing the implantable layer.

BACKGROUND

The present invention relates to surgical instruments and, in variousarrangements, to surgical stapling and cutting instruments and staplecartridges therefor that are designed to staple and cut tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of this invention, and the manner ofattaining them, will become more apparent and the invention itself willbe better understood by reference to the following description ofembodiments of the invention taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a left front perspective view of a surgical stapling andsevering instrument with a handle portion;

FIG. 2 is a perspective view of a two-piece knife and firing bar(“E-beam”) of the surgical stapling and severing instrument of FIG. 1;

FIG. 3 is a perspective view of a wedge sled of a staple cartridge of astaple applying assembly;

FIG. 4 is a longitudinal cross-sectional view of an anvil in a closedposition and a staple cartridge comprising a rigid support portion and acompressible tissue thickness compensator illustrated with staples beingmoved from an unfired position to a fired position during a firstsequence;

FIG. 5 is another cross-sectional view of the anvil and the staplecartridge of FIG. 4 illustrating the anvil in an open position after thefiring sequence has been completed;

FIG. 6 is an exploded perspective view of a tissue thickness compensatorand a staple cartridge assembly;

FIG. 7 is a partial cross-sectional view of the staple cartridgeassembly of FIG. 6, illustrating unfired staples positioned in staplecavities of a staple cartridge body and partially embedded in a tissuethickness compensator;

FIG. 8 is a partial cross-sectional view of the staple cartridgeassembly of FIG. 6, illustrating fired staples ejected from the staplecavities of the staple cartridge body and formed against an anvil, andfurther illustrating the tissue thickness compensator and tissuecaptured within the staple entrapment area of the formed staples;

FIG. 9 is a partial perspective view of an end effector of a surgicalfastening instrument illustrated with some portions removed and otherportions illustrated in cross-section; moreover, a cutting member of theend effector is illustrated in a partially advanced position;

FIG. 10 is a partial cross-sectional end view of the end effector ofFIG. 9 illustrated with patient tissue captured between an anvil and atissue thickness compensator of the end effector; moreover, staplesremovably stored within a cartridge body of the end effector areillustrated in an unfired position and the cutting member of the endeffector is illustrated in an unadvanced position which is proximal tothe tissue thickness compensator;

FIG. 11 is a partial cross-sectional end view of the end effector ofFIG. 9 illustrated with the staples in a fired position and the cuttingmember in a partially advanced position in which the patient tissue hasbeen at least partially transected;

FIG. 12 is a partial cross-sectional end view of the end effector ofFIG. 9 illustrated with the staples in a fired position and the cuttingmember in an advanced position in which at least a portion of the tissuethickness compensator has been transected by the cutting member;

FIG. 13 is a perspective view of a fastener cartridge including a tissuethickness compensator;

FIG. 14 is a cross-sectional view of the tissue thickness compensator ofFIG. 13 illustrating a cutting member positioned relative to a proximalend of the tissue thickness compensator.

FIG. 15 is an exploded view of a tissue thickness compensator assembly;

FIG. 16 is a perspective view of layer of a tissue thickness compensatorassembly;

FIG. 17 is a cross-sectional view of the tissue thickness compensatorassembly of FIG. 15;

FIG. 18 is a cross-sectional perspective view of an assembled tissuethickness compensator assembly and a mold for assembling the same;

FIG. 19 is a perspective view of the assembled tissue thicknesscompensator assembly of FIG. 18;

FIG. 20 is a perspective view of a tissue thickness compensator assemblyand a mold for assembling the same;

FIG. 21 is a perspective view of a tissue thickness compensator assemblyand a mold for assembling the same;

FIG. 22 is a cross-sectional perspective view of the tissue thicknesscompensator assembly of FIG. 21 and the mold of FIG. 21 for assemblingthe same;

FIG. 23 is a perspective view of an end effector comprising a tissuethickness compensator;

FIG. 24 is a perspective view of the end effector and the tissuethickness compensator of FIG. 23 and a modifying member modifying thetissue thickness compensator;

FIG. 25 is a perspective view of the end effector of FIG. 23 comprisingthe modified tissue thickness compensator of FIG. 24;

FIG. 26 is a cross-sectional perspective view of a tissue thicknesscompensator;

FIG. 27 is a cross-sectional perspective view of a mold for modifyingthe tissue thickness compensator of FIG. 26;

FIG. 28 is a cross-sectional perspective view of the tissue thicknesscompensator of FIG. 26 after modification by the mold of FIG. 27;

FIG. 29 is a cross-sectional perspective view of a tissue thicknesscompensator;

FIG. 30 is a cross-sectional perspective view of a mold for modifyingthe tissue thickness compensator of FIG. 29;

FIG. 31 is a cross-sectional perspective view of the tissue thicknesscompensator of FIG. 29 after modification by the mold of FIG. 30;

FIG. 32 is a cross-sectional perspective view of a tissue thicknesscompensator;

FIG. 33 is a cross-sectional perspective view of a mold for modifyingthe tissue thickness compensator of FIG. 32;

FIG. 34 is a cross-sectional perspective view of the tissue thicknesscompensator of FIG. 32 after modification by the mold of FIG. 33;

FIG. 35 is a cross-sectional perspective view of a tissue thicknesscompensator including a first height;

FIG. 36 is a cross-sectional perspective view of the tissue thicknesscompensator of FIG. 35 after modification to change the first height toa second height;

FIG. 37 is a cross-sectional view of a mold for modifying the tissuethickness compensator of FIG. 35;

FIG. 38 is a cross-sectional perspective view of a tissue thicknesscompensator;

FIG. 39 is a cross-sectional perspective view the tissue thicknesscompensator of FIG. 38 after modification;

FIG. 40 is a graph illustrating the effect of compression forces on aspring rate of a tissue thickness compensator;

FIG. 41 is a cross-sectional perspective view of a tissue thicknesscompensator;

FIG. 42 is a cross-sectional perspective view of a space creator formodifying the tissue thickness compensator of FIG. 41;

FIG. 43 is a cross-sectional perspective view of the tissue thicknesscompensator of FIG. 41 after modification by the space creator of FIG.42;

FIG. 44 is a partial cross-sectional elevational view of a fastenercartridge for use with a surgical instrument including a firing memberin accordance with at least one embodiment illustrated with portionsremoved;

FIG. 45 is a partial cross-sectional elevational view depicting a tissuethickness compensator of the fastener cartridge of FIG. 44 being removedfrom the fastener cartridge and the firing member of FIG. 44 illustratedin a locked-out condition;

FIG. 46 is a partial perspective view of the tissue thicknesscompensator of FIG. 45;

FIG. 47 is a partial perspective view a tissue thickness compensator inaccordance with at least one embodiment;

FIG. 48 is a partial cross-sectional elevational view of an end effectorof a surgical instrument comprising a fastener cartridge including thetissue thickness compensator of FIG. 47, a sled, and a firing membersupported by the sled illustrated with portions removed;

FIG. 49 is a partial cross-sectional elevational view of the endeffector of FIG. 48 illustrating the firing member in a partially-firedposition;

FIG. 50 is a partial cross-sectional elevational view of the endeffector of FIG. 48 illustrating the tissue thickness compensatorremoved from the fastener cartridge and the firing member in alocked-out condition;

FIG. 51 is a partial perspective view of a fastener cartridge inaccordance with at least one embodiment illustrated with portionsremoved;

FIG. 52 is a perspective view of a sled of the fastener cartridge ofFIG. 51;

FIG. 53 is a partial perspective view of the fastener cartridge of FIG.51;

FIG. 54 is an elevational view of a sled in accordance with at least oneembodiment;

FIG. 55 is a perspective view of a sled in accordance with at least oneembodiment illustrated in an unlocked configuration;

FIG. 56 is a perspective view of the sled of FIG. 55 illustrated in alocked-out configuration;

FIG. 57 is a partial cross-sectional elevational view of the sled ofFIG. 55 positioned within a fastener cartridge illustrating the sled inits unlocked configuration, a firing member supported by the sled, and atissue thickness compensator of the fastener cartridge engaged with thesled;

FIG. 58 is a partial cross-sectional elevational view of the tissuethickness compensator of FIG. 57 being removed from the fastenercartridge of FIG. 57 which has placed the sled of FIG. 55 in itslocked-out configuration and the firing member of FIG. 57 in alocked-out condition;

FIG. 59 is a partial cross-sectional elevational view of a sledpositioned at the proximal end of a fastener cartridge in accordancewith at least one embodiment illustrated with portions removed;

FIG. 60 is a partial cross-sectional elevational view of the sled ofFIG. 59 illustrated at the distal end of the fastener cartridge;

FIG. 61 is a perspective view of a sled in accordance with at least oneembodiment;

FIG. 62 is a diagram depicting a staple comprising a plurality of barbsin accordance with at least one embodiment, wherein the staple isillustrated in an unformed configuration and a deformed configuration;

FIG. 63 is an elevational view of a staple comprising a plurality ofbarbs in accordance with at least one embodiment, wherein the staple ispositioned within a staple cavity in an unfired position;

FIG. 64 is an elevational view of a staple including a plurality ofbarbs in accordance with at least one embodiment;

FIG. 65 is an elevational view of a staple including a plurality ofbarbs in accordance with at least one embodiment;

FIG. 66 is an elevational view of a staple including a plurality ofbarbs in accordance with at least one embodiment;

FIG. 67 is an elevational view of a staple including a plurality ofbarbs in accordance with at least one embodiment;

FIG. 68 is an elevational view of the staple including a plurality ofbarbs in accordance with at least one embodiment, wherein the staple ispositioned within a staple cavity in an unfired position;

FIG. 69 is a plan view of the staple and the staple cavity of FIG. 68;

FIG. 70 is a partial perspective view of a barbed staple leg inaccordance with at least one embodiment;

FIG. 71 is a partial perspective view of a barbed staple leg of thestaple of FIG. 68;

FIG. 71A is a cross-sectional plan view of the barbed staple leg of FIG.71;

FIG. 72 is a partial perspective view of a barbed staple leg inaccordance with at least one embodiment; and

FIG. 73 is a partial perspective view of a barbed staple leg inaccordance with at least one embodiment.

DETAILED DESCRIPTION

The Applicant of the present application also owns the U.S. PatentApplications identified below which are each herein incorporated byreference in their respective entirety:

-   U.S. patent application Ser. No. 12/894,311, entitled SURGICAL    INSTRUMENTS WITH RECONFIGURABLE SHAFT SEGMENTS; now U.S. Pat. No.    8,763,877;-   U.S. patent application Ser. No. 12/894,340, entitled SURGICAL    STAPLE CARTRIDGES SUPPORTING NON-LINEARLY ARRANGED STAPLES AND    SURGICAL STAPLING INSTRUMENTS WITH COMMON STAPLE-FORMING POCKETS;    now U.S. Pat. No. 8,899,463;-   U.S. patent application Ser. No. 12/894,327, entitled JAW CLOSURE    ARRANGEMENTS FOR SURGICAL INSTRUMENTS; now U.S. Pat. No. 8,978,956;-   U.S. patent application Ser. No. 12/894,351, entitled SURGICAL    CUTTING AND FASTENING INSTRUMENTS WITH SEPARATE AND DISTINCT    FASTENER DEPLOYMENT AND TISSUE CUTTING SYSTEMS; now U.S. Pat. No.    9,113,864;-   U.S. patent application Ser. No. 12/894,338, entitled IMPLANTABLE    FASTENER CARTRIDGE HAVING A NON-UNIFORM ARRANGEMENT; now U.S. Pat.    No. 8,864,007;-   U.S. patent application Ser. No. 12/894,369, entitled IMPLANTABLE    FASTENER CARTRIDGE COMPRISING A SUPPORT RETAINER; now U.S. Patent    Publication No. 2012/0080344;-   U.S. patent application Ser. No. 12/894,312, entitled IMPLANTABLE    FASTENER CARTRIDGE COMPRISING MULTIPLE LAYERS; now U.S. Pat. No.    8,925,782;-   U.S. patent application Ser. No. 12/894,377, entitled SELECTIVELY    ORIENTABLE IMPLANTABLE FASTENER CARTRIDGE; now U.S. Pat. No.    8,393,514;-   U.S. patent application Ser. No. 12/894,339, entitled SURGICAL    STAPLING INSTRUMENT WITH COMPACT ARTICULATION CONTROL ARRANGEMENT;    now U.S. Pat. No. 8,840,003;-   U.S. patent application Ser. No. 12/894,360, entitled SURGICAL    STAPLING INSTRUMENT WITH A VARIABLE STAPLE FORMING SYSTEM; now U.S.    Pat. No. 9,113,862;-   U.S. patent application Ser. No. 12/894,322, entitled SURGICAL    STAPLING INSTRUMENT WITH INTERCHANGEABLE STAPLE CARTRIDGE    ARRANGEMENTS; now U.S. Pat. No. 8,740,034;-   U.S. patent application Ser. No. 12/894,350, entitled SURGICAL    STAPLE CARTRIDGES WITH DETACHABLE SUPPORT STRUCTURES; now U.S.    Patent Publication No. 2012/0080478;-   U.S. patent application Ser. No. 12/894,383, entitled IMPLANTABLE    FASTENER CARTRIDGE COMPRISING BIOABSORBABLE LAYERS; now U.S. Pat.    No. 8,752,699;-   U.S. patent application Ser. No. 12/894,389, entitled COMPRESSIBLE    FASTENER CARTRIDGE; now U.S. Pat. No. 8,740,037;-   U.S. patent application Ser. No. 12/894,345, entitled FASTENERS    SUPPORTED BY A FASTENER CARTRIDGE SUPPORT; now U.S. Pat. No.    8,783,542;-   U.S. patent application Ser. No. 12/894,306, entitled COLLAPSIBLE    FASTENER CARTRIDGE; now U.S. Pat. No. 9,044,227;-   U.S. patent application Ser. No. 12/894,318, entitled FASTENER    SYSTEM COMPRISING A PLURALITY OF CONNECTED RETENTION MATRIX    ELEMENTS; now U.S. Pat. No. 8,814,024;-   U.S. patent application Ser. No. 12/894,330, entitled FASTENER    SYSTEM COMPRISING A RETENTION MATRIX AND AN ALIGNMENT MATRIX; now    U.S. Pat. No. 8,757,465;-   U.S. patent application Ser. No. 12/894,361, entitled FASTENER    SYSTEM COMPRISING A RETENTION MATRIX; now U.S. Pat. No. 8,529,600;-   U.S. patent application Ser. No. 12/894,367, entitled FASTENING    INSTRUMENT FOR DEPLOYING A FASTENER SYSTEM COMPRISING A RETENTION    MATRIX; now U.S. Pat. No. 9,033,203;-   U.S. patent application Ser. No. 12/894,388, entitled FASTENER    SYSTEM COMPRISING A RETENTION MATRIX AND A COVER; now U.S. Pat. No.    8,474,677;-   U.S. patent application Ser. No. 12/894,376, entitled FASTENER    SYSTEM COMPRISING A PLURALITY OF FASTENER CARTRIDGES; now U.S. Pat.    No. 9,044,228;-   U.S. patent application Ser. No. 13/097,865, entitled SURGICAL    STAPLER ANVIL COMPRISING A PLURALITY OF FORMING POCKETS; now U.S.    Pat. No. 9,295,464;-   U.S. patent application Ser. No. 13/097,936, entitled TISSUE    THICKNESS COMPENSATOR FOR A SURGICAL STAPLER; now U.S. Pat. No.    8,657,176;-   U.S. patent application Ser. No. 13/097,954, entitled STAPLE    CARTRIDGE COMPRISING A VARIABLE THICKNESS COMPRESSIBLE PORTION; now    U.S. Patent Publication No. 2012/0080340;-   U.S. patent application Ser. No. 13/097,856, entitled STAPLE    CARTRIDGE COMPRISING STAPLES POSITIONED WITHIN A COMPRESSIBLE    PORTION THEREOF; now U.S. Patent Publication No. 2012/0080336;-   U.S. patent application Ser. No. 13/097,928, entitled TISSUE    THICKNESS COMPENSATOR COMPRISING DETACHABLE PORTIONS; now U.S. Pat.    No. 8,746,535;-   U.S. patent application Ser. No. 13/097,891, entitled TISSUE    THICKNESS COMPENSATOR FOR A SURGICAL STAPLER COMPRISING AN    ADJUSTABLE ANVIL; now U.S. Pat. No. 8,864,009;-   U.S. patent application Ser. No. 13/097,948, entitled STAPLE    CARTRIDGE COMPRISING AN ADJUSTABLE DISTAL PORTION; now U.S. Pat. No.    8,978,954;-   U.S. patent application Ser. No. 13/097,907, entitled COMPRESSIBLE    STAPLE CARTRIDGE ASSEMBLY; now U.S. Pat. No. 9,301,755;-   U.S. patent application Ser. No. 13/097,861, entitled TISSUE    THICKNESS COMPENSATOR COMPRISING PORTIONS HAVING DIFFERENT    PROPERTIES; now U.S. Pat. No. 9,113,865;-   U.S. patent application Ser. No. 13/097,869, entitled STAPLE    CARTRIDGE LOADING ASSEMBLY; now U.S. Pat. No. 8,857,694;-   U.S. patent application Ser. No. 13/097,917, entitled COMPRESSIBLE    STAPLE CARTRIDGE COMPRISING ALIGNMENT MEMBERS; now U.S. Pat. No.    8,777,004;-   U.S. patent application Ser. No. 13/097,873, entitled STAPLE    CARTRIDGE COMPRISING A RELEASABLE PORTION; now U.S. Pat. No.    8,740,038;-   U.S. patent application Ser. No. 13/097,938, entitled STAPLE    CARTRIDGE COMPRISING COMPRESSIBLE DISTORTION RESISTANT COMPONENTS;    now U.S. Pat. No. 9,016,542;-   U.S. patent application Ser. No. 13/097,924, entitled STAPLE    CARTRIDGE COMPRISING A TISSUE THICKNESS COMPENSATOR; now U.S. Pat.    No. 9,168,038;-   U.S. patent application Ser. No. 13/242,029, entitled SURGICAL    STAPLER WITH FLOATING ANVIL; now U.S. Pat. No. 8,893,949;-   U.S. patent application Ser. No. 13/242,066, entitled CURVED END    EFFECTOR FOR A STAPLING INSTRUMENT; now U.S. Patent Publication No.    2012/0080498;-   U.S. patent application Ser. No. 13/242,086, entitled STAPLE    CARTRIDGE INCLUDING COLLAPSIBLE DECK; now U.S. Pat. No. 9,055,941;-   U.S. patent application Ser. No. 13/241,912, entitled STAPLE    CARTRIDGE INCLUDING COLLAPSIBLE DECK ARRANGEMENT; now U.S. Pat. No.    9,050,084;-   U.S. patent application Ser. No. 13/241,922, entitled SURGICAL    STAPLER WITH STATIONARY STAPLE DRIVERS; now U.S. Pat. No. 9,216,019;-   U.S. patent application Ser. No. 13/241,637, entitled SURGICAL    INSTRUMENT WITH TRIGGER ASSEMBLY FOR GENERATING MULTIPLE ACTUATION    MOTIONS; now U.S. Pat. No. 8,789,741;-   U.S. patent application Ser. No. 13/241,629, entitled SURGICAL    INSTRUMENT WITH SELECTIVELY ARTICULATABLE END EFFECTOR; now U.S.    Patent Publication No. 2012/0074200;-   U.S. application Ser. No. 13/433,096, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING A PLURALITY OF CAPSULES; now U.S. Pat. No.    9,301,752;-   U.S. application Ser. No. 13/433,103, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING A PLURALITY OF LAYERS; now U.S. Pat. No.    9,433,419;-   U.S. application Ser. No. 13/433,098, entitled EXPANDABLE TISSUE    THICKNESS COMPENSATOR; now U.S. Pat. No. 9,301,753;-   U.S. application Ser. No. 13/433,102, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING A RESERVOIR; now U.S. Pat. No. 9,232,941;-   U.S. application Ser. No. 13/433,114, entitled RETAINER ASSEMBLY    INCLUDING A TISSUE THICKNESS COMPENSATOR; now U.S. Pat. No.    9,386,988;-   U.S. application Ser. No. 13/433,136, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING AT LEAST ONE MEDICAMENT; now U.S. Patent    Publication No. 2012/0241492;-   U.S. application Ser. No. 13/433,141, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING CONTROLLED RELEASE AND EXPANSION; now U.S.    Patent Publication No. 2012/0241493;-   U.S. application Ser. No. 13/433,144, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING FIBERS TO PRODUCE A RESILIENT LOAD; now U.S.    Pat. No. 9,277,919;-   U.S. application Ser. No. 13/433,148, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING STRUCTURE TO PRODUCE A RESILIENT LOAD; now    U.S. Pat. No. 9,220,500;-   U.S. application Ser. No. 13/433,155, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING RESILIENT MEMBERS; now U.S. Pat. No.    9,480,476;-   U.S. application Ser. No. 13/433,163, entitled METHODS FOR FORMING    TISSUE THICKNESS COMPENSATOR ARRANGEMENTS FOR SURGICAL STAPLERS; now    U.S. Patent Publication No. 2012/0248169;-   U.S. application Ser. No. 13/433,167, entitled TISSUE THICKNESS    COMPENSATORS; now U.S. Pat. No. 9,220,501;-   U.S. application Ser. No. 13/433,175, entitled LAYERED TISSUE    THICKNESS COMPENSATOR; now U.S. Pat. No. 9,332,974;-   U.S. application Ser. No. 13/433,179, entitled TISSUE THICKNESS    COMPENSATORS FOR CIRCULAR SURGICAL STAPLERS; now U.S. Pat. No.    9,364,233;-   U.S. application Ser. No. 13/763,028, entitled ADHESIVE FILM    LAMINATE; now U.S. Pat. No. 9,282,962;-   U.S. application Ser. No. 13/433,115, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING CAPSULES DEFINING A LOW PRESSURE ENVIRONMENT;    now U.S. Pat. No. 9,204,880;-   U.S. application Ser. No. 13/433,118, entitled TISSUE THICKNESS    COMPENSATOR COMPRISED OF A PLURALITY OF MATERIALS; now U.S. Pat. No.    9,414,838;-   U.S. application Ser. No. 13/433,135, entitled MOVABLE MEMBER FOR    USE WITH A TISSUE THICKNESS COMPENSATOR; now U.S. Pat. No.    9,517,063;-   U.S. application Ser. No. 13/433,140, entitled TISSUE THICKNESS    COMPENSATOR AND METHOD FOR MAKING THE SAME; now U.S. Pat. No.    9,241,714;-   U.S. application Ser. No. 13/433,129, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING A PLURALITY OF MEDICAMENTS; now U.S. Pat. No.    9,211,120;-   U.S. application Ser. No. 11/216,562, entitled STAPLE CARTRIDGES FOR    FORMING STAPLES HAVING DIFFERING FORMED STAPLE HEIGHTS, now U.S.    Pat. No. 7,669,746;-   U.S. application Ser. No. 11/714,049, entitled SURGICAL STAPLING    DEVICE WITH ANVIL HAVING STAPLE FORMING POCKETS OF VARYING DEPTHS,    now U.S. Patent Publication No. 2007/0194082;-   U.S. application Ser. No. 11/711,979, entitled SURGICAL STAPLING    DEVICES THAT PRODUCE FORMED STAPLES HAVING DIFFERENT LENGTHS, now    U.S. Pat. No. 8,317,070;-   U.S. application Ser. No. 11/711,975, entitled SURGICAL STAPLING    DEVICE WITH STAPLE DRIVERS OF DIFFERENT HEIGHT, now U.S. Patent    Publication No. 2007/0194079;-   U.S. application Ser. No. 11/711,977, entitled SURGICAL STAPLING    DEVICE WITH STAPLE DRIVER THAT SUPPORTS MULTIPLE WIRE DIAMETER    STAPLES, now U.S. Pat. No. 7,673,781;-   U.S. application Ser. No. 11/712,315, entitled SURGICAL STAPLING    DEVICE WITH MULTIPLE STACKED ACTUATOR WEDGE CAMS FOR DRIVING STAPLE    DRIVERS, now U.S. Pat. No. 7,500,979;-   U.S. application Ser. No. 12/038,939, entitled STAPLE CARTRIDGES FOR    FORMING STAPLES HAVING DIFFERING FORMED STAPLE HEIGHTS, now U.S.    Pat. No. 7,934,630;-   U.S. application Ser. No. 13/020,263, entitled SURGICAL STAPLING    SYSTEMS THAT PRODUCE FORMED STAPLES HAVING DIFFERENT LENGTHS, now    U.S. Pat. No. 8,636,187;-   U.S. application Ser. No. 13/118,278, entitled    ROBOTICALLY-CONTROLLED SURGICAL STAPLING DEVICES THAT PRODUCE FORMED    STAPLES HAVING DIFFERENT LENGTHS, now U.S. Pat. No. 9,237,891;-   U.S. application Ser. No. 13/369,629, entitled    ROBOTICALLY-CONTROLLED CABLE-BASED SURGICAL END EFFECTORS, now U.S.    Pat. No. 8,800,838;-   U.S. application Ser. No. 12/695,359, entitled SURGICAL STAPLING    DEVICES FOR FORMING STAPLES WITH DIFFERENT FORMED HEIGHTS, now U.S.    Pat. No. 8,464,923;-   U.S. application Ser. No. 13/072,923, entitled STAPLE CARTRIDGES FOR    FORMING STAPLES HAVING DIFFERING FORMED STAPLE HEIGHTS, now U.S.    Pat. No. 8,567,656;-   U.S. application Ser. No. 13/766,325, entitled LAYER OF MATERIAL FOR    A SURGICAL END EFFECTOR; now U.S. Patent Publication No.    2013/0256380;-   U.S. application Ser. No. 13/763,078, entitled ANVIL LAYER ATTACHED    TO A PROXIMAL END OF AN END EFFECTOR; now U.S. Patent Publication    No. 2013/0256383;-   U.S. application Ser. No. 13/763,094, entitled LAYER COMPRISING    DEPLOYABLE ATTACHMENT MEMBERS; now U.S. Patent Publication No.    2013/0256377;-   U.S. application Ser. No. 13/763,106, entitled END EFFECTOR    COMPRISING A DISTAL TISSUE ABUTMENT MEMBER; now U.S. Patent    Publication No. 2013/0256378;-   U.S. application Ser. No. 13/433,147, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING CHANNELS; now U.S. Pat. No. 9,351,730;-   U.S. application Ser. No. 13/763,112, entitled SURGICAL STAPLING    CARTRIDGE WITH LAYER RETENTION FEATURES; now U.S. Patent Publication    No. 2013/0256379;-   U.S. application Ser. No. 13/763,035, entitled ACTUATOR FOR    RELEASING A TISSUE THICKNESS COMPENSATOR FROM A FASTENER CARTRIDGE;    now U.S. Patent Publication No. 2013/0214030;-   U.S. application Ser. No. 13/763,042, entitled RELEASABLE TISSUE    THICKNESS COMPENSATOR AND FASTENER CARTRIDGE HAVING THE SAME; now    U.S. Patent Publication No. 2013/0221063;-   U.S. application Ser. No. 13/763,048, entitled FASTENER CARTRIDGE    COMPRISING A RELEASABLE TISSUE THICKNESS COMPENSATOR; now U.S.    Patent Publication No. 2013/0221064;-   U.S. application Ser. No. 13/763,054, entitled FASTENER CARTRIDGE    COMPRISING A CUTTING MEMBER FOR RELEASING A TISSUE THICKNESS    COMPENSATOR, now U.S. Pat. No. 9,272,406;-   U.S. application Ser. No. 13/763,065, entitled FASTENER CARTRIDGE    COMPRISING A RELEASABLY ATTACHED TISSUE THICKNESS COMPENSATOR; now    U.S. Pat. No. 9,566,061;-   U.S. application Ser. No. 13/763,021, entitled STAPLE CARTRIDGE    COMPRISING A RELEASABLE COVER, now U.S. Pat. No. 9,386,984;-   U.S. application Ser. No. 13/763,078, entitled ANVIL LAYER ATTACHED    TO A PROXIMAL END OF AN END EFFECTOR; now U.S. Patent Publication    No. 2013/0256383;-   U.S. application Ser. No. 13/763,095, entitled LAYER ARRANGEMENTS    FOR SURGICAL STAPLE CARTRIDGES; now U.S. Patent Publication No.    2013/0161374;-   U.S. application Ser. No. 13/463,147, entitled IMPLANTABLE    ARRANGEMENTS FOR SURGICAL STAPLE CARTRIDGES; now U.S. Patent    Publication No. 2013/0292398;-   U.S. application Ser. No. 13/763,192, entitled MULTIPLE THICKNESS    IMPLANTABLE LAYERS FOR SURGICAL STAPLING DEVICES; now U.S. Patent    Publication No. 2013/0146642;-   U.S. application Ser. No. 13/763,161, entitled RELEASABLE LAYER OF    MATERIAL AND SURGICAL END EFFECTOR HAVING THE SAME; now U.S. Patent    Publication No. 2013/0153641;-   U.S. application Ser. No. 13/763,177, entitled ACTUATOR FOR    RELEASING A LAYER OF MATERIAL FROM A SURGICAL END EFFECTOR; now U.S.    Patent Publication No. 2013/0146641;-   U.S. application Ser. No. 13/763,037, entitled STAPLE CARTRIDGE    COMPRISING A COMPRESSIBLE PORTION, now U.S. Patent Publication No.    2014/0224857;-   U.S. application Ser. No. 13/433,126, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING TISSUE INGROWTH FEATURES; now U.S. Pat. No.    9,320,523;-   U.S. application Ser. No. 13/433,132, entitled DEVICES AND METHODS    FOR ATTACHING TISSUE THICKNESS COMPENSATING MATERIALS TO SURGICAL    STAPLING INSTRUMENTS; now U.S. Patent Publication No. 2013/0256373.-   U.S. application Ser. No. 13/851,703, entitled FASTENER CARTRIDGE    COMPRISING A TISSUE THICKNESS COMPENSATOR INCLUDING OPENINGS    THEREIN, now U.S. Pat. No. 9,572,577;-   U.S. application Ser. No. 13/851,676, entitled TISSUE THICKNESS    COMPENSATOR COMPRISING A CUTTING MEMBER PATH, now U.S. Patent    Publication No. 2014/0291379;-   U.S. application Ser. No. 13/851,693, entitled FASTENER CARTRIDGE    ASSEMBLIES, now U.S. Pat. No. 9,332,984; and-   U.S. application Ser. No. 13/851,684, entitled FASTENER CARTRIDGE    COMPRISING A TISSUE THICKNESS COMPENSATOR AND A GAP SETTING ELEMENT,    now U.S. Patent Publication No. 2014/0291380.

Applicant of the present application also owns the following patentapplications that were filed on Feb. 24, 2014 and which are each hereinincorporated by reference in their respective entireties:

-   U.S. patent application Ser. No. 14/187,387, entitled STAPLE    CARTRIDGE INCLUDING A BARBED STAPLE, now U.S. Patent Publication No.    2014/0166724;-   U.S. patent application Ser. No. 14/187,395, entitled STAPLE    CARTRIDGE INCLUDING A BARBED STAPLE, now U.S. Patent Publication No.    2014/0166725;-   U.S. patent application Ser. No. 14/187,400, entitled STAPLE    CARTRIDGE INCLUDING A BARBED STAPLE, now U.S. Patent Publication No.    2014/0166726;-   U.S. patent application Ser. No. 14/187,383, entitled IMPLANTABLE    LAYERS AND METHODS FOR ALTERING IMPLANTABLE LAYERS FOR USE WITH    SURGICAL FASTENING INSTRUMENTS, now U.S. Pat. No. 9,839,422;-   U.S. patent application Ser. No. 14/187,390, entitled IMPLANTABLE    LAYERS AND METHODS FOR MODIFYING THE SHAPE OF THE IMPLANTABLE LAYERS    FOR USE WITH A SURGICAL FASTENING INSTRUMENT, now U.S. Pat. No.    9,839,423;-   U.S. patent application Ser. No. 14/187,389, entitled IMPLANTABLE    LAYER ASSEMBLIES, now U.S. Pat. No. 9,757,124;-   U.S. patent application Ser. No. 14/187,385, entitled IMPLANTABLE    LAYERS COMPRISING A PRESSED REGION, now U.S. Pat. No. 9,693,777; and-   U.S. patent application Ser. No. 14/187,384, entitled FASTENING    SYSTEM COMPRISING A FIRING MEMBER LOCKOUT, now U.S. Pat. No.    9,775,608.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those of ordinary skill in the art will understand that thedevices and methods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the various embodiments of the present invention is definedsolely by the claims. The features illustrated or described inconnection with one exemplary embodiment may be combined with thefeatures of other embodiments. Such modifications and variations areintended to be included within the scope of the present invention.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, a surgicalsystem, device, or apparatus that “comprises,” “has,” “includes” or“contains” one or more elements possesses those one or more elements,but is not limited to possessing only those one or more elements.Likewise, an element of a system, device, or apparatus that “comprises,”“has,” “includes” or “contains” one or more features possesses those oneor more features, but is not limited to possessing only those one ormore features.

The terms “proximal” and “distal” are used herein with reference to aclinician manipulating the handle portion of the surgical instrument.The term “proximal” referring to the portion closest to the clinicianand the term “distal” referring to the portion located away from theclinician. It will be further appreciated that, for convenience andclarity, spatial terms such as “vertical”, “horizontal”, “up”, and“down” may be used herein with respect to the drawings. However,surgical instruments are used in many orientations and positions, andthese terms are not intended to be limiting and/or absolute.

Various exemplary devices and methods are provided for performinglaparoscopic and minimally invasive surgical procedures. However, theperson of ordinary skill in the art will readily appreciate that thevarious methods and devices disclosed herein can be used in numeroussurgical procedures and applications including, for example, inconnection with open surgical procedures. As the present DetailedDescription proceeds, those of ordinary skill in the art will furtherappreciate that the various instruments disclosed herein can be insertedinto a body in any way, such as through a natural orifice, through anincision or puncture hole formed in tissue, etc. The working portions orend effector portions of the instruments can be inserted directly into apatient's body or can be inserted through an access device that has aworking channel through which the end effector and elongated shaft of asurgical instrument can be advanced.

Turning to the Drawings wherein like numerals denote like componentsthroughout the several views, FIG. 1 illustrates an exemplary surgicalstapling and severing instrument 8010 suitable for use with a tissuethickness compensator assembly as described in greater detail below. Thesurgical stapling and severing instrument 8010 can comprise an anvil8014 which may be repeatedly opened and closed about its pivotalattachment to an elongate staple channel 8016. A staple applyingassembly 8012 may comprise the anvil 8014 and the channel 8016, whereinthe assembly 8012 can be proximally attached to an elongate shaft 8018forming an implement portion 8022. When the staple applying assembly8012 is closed, or at least substantially closed, the implement portion8022 can present a sufficiently small cross-section suitable forinserting the staple applying assembly 8012 through a trocar. In variouscircumstances, the assembly 8012 can be manipulated by a handle 8020connected to the shaft 8018. The handle 8020 can comprise user controlssuch as a rotation knob 8030 that rotates the elongate shaft 8018 andthe staple applying assembly 8012 about a longitudinal axis of the shaft8018. A closure trigger 8026, which can pivot in front of a pistol grip8036 to close the staple applying assembly 8012. A closure releasebutton 8038 can be outwardly presented on the handle 8020 when theclosure trigger 8026 is clamped such that the release button 8038 can bedepressed to unclamp the closure trigger 8026 and open the stapleapplying assembly 8012, for example. A firing trigger 8034, which canpivot in front of the closure trigger 8026, can cause the stapleapplying assembly 8012 to simultaneously sever and staple tissue clampedtherein. In various circumstances, multiple firing strokes can beemployed using the firing trigger 8034 to reduce the amount of forcerequired to be applied by the surgeon's hand per stroke. In certainembodiments, the handle 8020 can comprise one or more rotatableindicator wheels such as, for example, rotatable indicator wheel 8041which can indicate the firing progress. A manual firing release lever8042 can allow the firing system to be retracted before full firingtravel has been completed, if desired, and, in addition, the firingrelease lever 8042 can allow a surgeon, or other clinician, to retractthe firing system in the event that the firing system binds and/orfails. Additional details on the surgical stapling and severinginstrument 8010 and other surgical stapling and severing instrumentssuitable for use with the present disclosure are described, for example,in U.S. patent application Ser. No. 13/851,693, entitled FASTENERCARTRIDGE ASSEMBLY, and filed on Mar. 27, 2013, the entire disclosure ofwhich is incorporated herein by reference. Furthermore, powered surgicalstapling and severing instruments can also be utilized with the presentdisclosure. See, for example, U.S. Patent Application Publication No.2009/0090763 A1, entitled POWERED SURGICAL STAPLING DEVICE, and filed onAug. 8, 2008, the entire disclosure of which is incorporated herein byreference.

With reference to FIGS. 2 and 3, a firing assembly such as, for example,firing assembly 9090 can be utilized with the surgical stapling andsevering instrument 8010 to advance a wedge sled 9126 which comprises aplurality of wedges 9204 configured to deploy staples from the stapleapplying assembly 8012 into tissue captured between the anvil 8014 andthe elongate staple channel 8016. Furthermore, an E-beam 9102 at adistal portion of the firing assembly 9090 may facilitate separateclosure and firing as well as spacing of the anvil 8014 from theelongate staple channel 8016 during firing. The E-beam 9102 may includea pair of top pins 9110, a pair of middle pins 9112 which may followportion 9218 of the wedge sled 9126, and a bottom pin or foot 9114, aswell as a sharp cutting edge 9116 which can be configured to sever thecaptured tissue as the firing assembly 9090 is advanced distally. Inaddition, integrally formed and proximally projecting top guide 9118 andmiddle guide 9120 bracketing each vertical end of the cutting edge 9116may further define a tissue staging area 9122 assisting in guidingtissue to the sharp cutting edge 9116 prior to being severed. The middleguide 9120 may also serve to engage and fire the staple applyingassembly 8012 by abutting a stepped central member 9124 of the wedgesled 9126 (FIG. 2) that effects staple formation by the staple applyingassembly 8012.

In various circumstances, a staple cartridge can comprise means forcompensating for thickness of tissue captured within staples deployedfrom a staple cartridge. Referring to FIG. 4, a staple cartridge, suchas staple cartridge 10000, for example, can be utilized with thesurgical stapling and severing instrument 8010 and can include a rigidfirst portion, such as support portion 10010, for example, and acompressible second portion, such as tissue thickness compensator 10020,for example. The support portion 10010 can comprise a cartridge body anda plurality of staple cavities 10012. A staple 10030, for example, canbe removably positioned in each staple cavity 10012. Referring primarilyto FIGS. 4 and 5, each staple 10030 can comprise a base 10031 and one ormore legs 10032 extending from the base 10031. Prior to the staples10030 being deployed, the bases 10031 of the staples 10030 can besupported by staple drivers positioned within the support portion 10010and, concurrently, the legs 10032 of the staples 10030 can be at leastpartially contained within the staple cavities 10012. In variouscircumstances, the staples 10030 can be deployed between an unfiredposition and a fired position such that the legs 10032 move through thetissue thickness compensator 10020, penetrate through a top surface ofthe tissue thickness compensator 10020, penetrate the tissue T, andcontact an anvil positioned opposite the staple cartridge 10000. As thelegs 10032 are deformed against the anvil, the legs 10032 of each staple10030 can capture a portion of the tissue thickness compensator 10020and a portion of the tissue T within each staple 10030 and apply acompressive force to the tissue. Further to the above, the legs 10032 ofeach staple 10030 can be deformed downwardly toward the base 10031 ofthe staple to form a staple entrapment area in which the tissue T andthe tissue thickness compensator 10020 can be captured. In variouscircumstances, the staple entrapment area can be defined between theinner surfaces of the deformed legs 10032 and the inner surface of thebase 10031. The size of the entrapment area for a staple can depend onseveral factors such as the length of the legs, the diameter of thelegs, the width of the base, and/or the extent in which the legs aredeformed, for example.

In use, further to the above and referring primarily to FIG. 4, ananvil, such as anvil 8014 of the surgical stapling and severinginstrument 8010, can be moved into a closed position opposite the staplecartridge 10000 by depressing the closure trigger 8026 to advance theE-beam 9102. The anvil 8014 can position tissue against the tissuethickness compensator 10020 and, in various circumstances, compress thetissue thickness compensator 10020 against the support portion 10010,for example. Once the anvil 8014 has been suitably positioned, thestaples 10030 can be deployed, as also illustrated in FIG. 4. In variouscircumstances, as mentioned above, a staple-firing sled 10050, which issimilar in many respects to the sled 9126 (See FIG. 3), can be movedfrom a proximal end of the staple cartridge 10000 toward a distal end10002, as illustrated in FIG. 5. As the firing assembly 9090 isadvanced, the sled 10050 can contact the staple drivers 10040 and liftthe staple drivers 10040 upwardly within the staple cavities 10012. Inat least one example, the sled 10050 and the staple drivers 10040 caneach comprise one or more ramps, or inclined surfaces, which canco-operate to move the staple drivers 10040 upwardly from their unfiredpositions. As the staple drivers 10040 are lifted upwardly within theirrespective staple cavities 10012, the staple drivers 10040 can lift thestaples 10030 upwardly such that the staples 10030 can emerge from theirstaple cavities 10012. In various circumstances, the sled 10050 can moveseveral staples upwardly at the same time as part of a firing sequence.

As discussed above, and referring to FIG. 5, the staple legs 10032 ofthe staples 10030 can extend into the compensator 10020 beyond thesupport portion 10010 when the staples 10030 are in their unfiredpositions. In various circumstances, the tips of the staple legs 10032,or any other portion of the staple legs 10032, may not protrude througha top tissue-contacting surface 10021 of the tissue thicknesscompensator 10020 when the staples 10030 are in their unfired positions.In certain circumstances, the tips of the staple legs 10032 can comprisesharp tips which can incise and penetrate the tissue thicknesscompensator 10020.

In various circumstances, it may be preferable to prevent and/or limitfrictional forces between a tissue thickness compensator and a staple.Referring now to FIGS. 6-8, a tissue thickness compensator 20220 for usewith a staple cartridge assembly 20200 can include a plurality ofclearance apertures 20224 extending at least partially through thetissue thickness compensator 20220. In various circumstances, the staplecartridge assembly 20200 can include a staple cartridge body 20210 and atissue thickness compensator 20220 releasably secured relative to thestaple cartridge body 20210. The cartridge body 20210 can include acartridge deck 20211 and a plurality of staple cavities 20212 definedthrough the cartridge deck 20211 and into the body of the staplecartridge body 20210, for example. Staples 20230 can be removablypositioned in the staple cavities 20212, for example. The tissuethickness compensator 20220 can include a tissue-contacting surface20221 (FIG. 7) and a deck-contacting surface 20222 (FIG. 6). Thedeck-contacting surface 20222 can be releasably positioned against thedeck 20211 of the cartridge body 20210, for example, and thetissue-contacting surface 20221 can be positioned against tissue T to bestapled, for example. Clearance apertures 20224 can extend through thedeck-contacting surface 20222 and into the tissue thickness compensator20220 and may comprise holes, slits, gaps, bores, openings, and/orcleared pathways, for example, within the tissue thickness compensator20220.

Referring primarily to FIGS. 7 and 8, staples 20230 can be positioned inthe staple cavities 20212 of the cartridge body 20210. Each staple 20230can include a base 20231 and a pair of staple legs 20232, for example,which can extend from the base 20231. Each staple leg 20232 can extendfrom opposite ends of the base 20231. Referring primarily to FIG. 7, oneor more of the clearance apertures 20224 in the tissue thicknesscompensator 20220 can include an opening in the deck-contacting surface20222. The opening of a clearance aperture 20224 can be aligned with acorresponding staple leg 20232 that is positioned in a staple cavity20212. For example, a single staple leg 20232 can be aligned with theopening of a single clearance aperture 20224 when the tissue thicknesscompensator 20220 is secured relative to the cartridge body 20210. Incertain circumstances, a staple leg 20232 can extend into each clearanceaperture 20224, such that at least a portion of the staple 20230 isembedded in the tissue thickness compensator 20220, for example. Forexample, referring primarily to FIG. 7, a staple 20230 can include afirst staple leg 20232 a and a second staple leg 20232 b. Furthermore,the tissue thickness compensator 20220 can include a first clearanceaperture 20224 a aligned with the first staple leg 20232 a, and a secondclearance aperture 20224 b aligned with the second staple leg 20232 b,for example. Prior to deployment of the staple 20230, the first stapleleg 20232 a can extend partially through the first clearance aperture20224 a, and the second staple leg 20232 b can extend partially throughthe second clearance aperture 20224 b, for example. The tissue thicknesscompensator 20220 can include additional clearance apertures 20224 thatare not aligned with staple legs 20232, for example. In certaincircumstances, the staple cartridge assembly 20200 can includeadditional staples 20230 and/or staple legs 20232 that are not alignedwith clearance apertures 20224, for example.

The staples 20230 can be moveable from an unfired configuration (FIG. 7)to a fired configuration (FIG. 8). Each staple 20230 can be moved alonga staple axis when moving between the unfired configuration and thefired configuration. When in the unfired configuration, the staple legs20232 can extend from the staple cavities 20212 and into the tissuethickness compensator 20220, for example. The staple legs 20232 can bepartially embedded in the tissue thickness compensator 20220 when thestaples 20230 are in the unfired configuration, for example.Furthermore, at least a portion of the staple legs 20232 can be alignedwith and/or positioned within the clearance apertures 20224 of thetissue thickness compensator 20220 when the staples are in the unfiredconfiguration, for example. In other circumstances, the staple legs20232 can be positioned entirely within the staple cavity 20212 when inthe unfired configuration, and can be aligned with the clearanceapertures 20224 positioned above the cartridge deck 20211 (FIG. 6), forexample.

The staples 20230 can move from the unfired configuration (FIG. 7) tothe fired configuration (FIG. 8) during a firing stroke, as describedherein. A staple driver 20240 can be positioned within each staplecavity 20212. The staple driver 20240 within each staple cavity 20212can be pushed toward the cartridge deck 20211 (FIG. 6), for example, todrive the staple 20230 into tissue T and toward an anvil 20260 (FIG. 8)which can be similar in many respects to other anvils described hereinsuch as, for example, the anvil 8014 (FIG. 1). As each staple 20230moves from the unfired configuration to the fired configuration, thestaple legs 20232 can move through the clearance apertures 20224 in thetissue thickness compensator 20220. The clearance apertures 20224 canhave a predefined trajectory within the tissue thickness compensator20220. For example, the clearance apertures 20224 can extend along anaxis that is perpendicular to and/or substantially perpendicular to thetissue-contacting surface 20221 (FIG. 7) and/or the deck-contactingsurface 20222 (FIG. 6) of the tissue thickness compensator 20220. Inother circumstances, the clearance apertures 20224 can extend along anaxis that is oriented at an oblique angle relative to thetissue-contacting surface 20221 and/or the deck-contacting surface 20222of the tissue thickness compensator 20220, for example. In certaincircumstances, a group of the clearance apertures 20224 can be parallel.In some circumstances, all of the clearance apertures 20224 within thetissue thickness compensator 20220 can be parallel, for example. Theclearance apertures 20224 can comprise a partially curved trajectoryand/or a partially linear trajectory. Other characteristics and featuresof the clearance apertures 20224 are described in greater detail in U.S.patent application Ser. No. 13/851,693, entitled FASTENER CARTRIDGEASSEMBLY, and filed on Mar. 27, 2013, the entire disclosure of which isincorporated herein by reference. Methods and techniques for modifying atissue thickness compensator to include clearance apertures such as, forexample, the clearance apertures 20224 are described below in greaterdetail.

Referring now to FIGS. 9-12, an end effector 22090 of a surgicalinstrument similar in many respects to the surgical instrument 8010, forexample, can comprise a first jaw including a fastener cartridgeassembly 22000 and a second jaw including an anvil 10060. The first jawcan include a staple cartridge channel 10070 which can be configured toremovably receive the cartridge assembly 22000. Alternatively, thestaple cartridge channel 10070 and the cartridge assembly 22000 cancomprise an integral unit. In various circumstances, the anvil 10060 canbe moved between an open position and a closed position (FIGS. 9-12). Inthe open position of the anvil 10060, the anvil 10060 can be positionedon a first side of a patient's tissue T (FIGS. 10-12) and the cartridgeassembly 22000 can be positioned on a second, or opposite, side of thetissue T, for example. When the anvil 10060 is moved into its closedposition, the anvil 10060 can compress the tissue T against thecartridge assembly 22000. Alternatively, the first jaw including thecartridge assembly 22000 can be moved relative to the anvil 10060. Afiring member 10052, which is similar in many respects to the firingassembly 9090 (FIG. 3), can be advanced distally from a proximal end22001 of the cartridge assembly 22000 toward a distal end 22002 of thecartridge assembly 22000 to eject fasteners, such as staples 22030, forexample, removably stored in a cartridge body 22010 of the cartridgeassembly 22000 as the firing member 10052 is advanced from the proximalend 22001 toward the distal end 22002 of the cartridge assembly 22000.

Further to the above, the staples 22030 can be supported by stapledrivers 10040 which are movably positioned within staple cavities 22012defined in the cartridge body 22010. Moreover, the firing member 10052can be configured to advance a staple-firing sled 10050 distally withinthe cartridge body 22010 as the firing member 10052 is moved from theproximal end 22001 toward the distal end 22002. In such circumstances,the staple-firing sled 10050 can be configured to lift the stapledrivers 10040, and the staples 22030 supported thereon, toward the anvil10060. In essence, further to the above, the staple drivers 10040 canmove the staples 22030 from an unfired position (FIG. 10) to a firedposition (FIGS. 11 and 12) wherein the staples 22030 can contact theanvil 10060 and be deformed between an undeformed configuration (FIG.10) and a deformed configuration (FIGS. 11 and 12). The anvil 10060 cancomprise forming pockets 10062 which can be configured to receive anddeform the staples 22030. Staples 22030 can be the same as or similar tostaples 10030, for example and/or any other staples disclosed herein,and, as such, staples 22030 are not described in greater detail herein.The reader will note, however, that the staples 22030 can comprise anysuitable shape and/or suitable dimensions, such as width and/or height,for example, in their undeformed configuration and/or their deformedconfiguration. For instance, the staples 22030 can, in certaincircumstances, comprise a height which does not extend above a decksurface 22011 of the cartridge body 22010 when the staples 22030 are intheir unfired positions while, in other circumstances, the staples 22030can comprise a height in which the legs of the staples 22030 extendupwardly from the deck surface 22011 when the staples 22030 are in theirunfired positions such that the legs of the staples 22030 are at leastpartially embedded in a tissue thickness compensator 22010 of thecartridge assembly 22000.

With continued reference to the embodiment depicted in FIGS. 9-12,further to the above, the cartridge assembly 22000 can comprise acartridge body 22010 and a tissue thickness compensator 22020. Invarious circumstances, the cartridge body 22010 can be similar to thesupport portion 10010, for example, in many respects and, as a result,many of such respects are not repeated herein for the sake of brevity.Furthermore, the tissue thickness compensator 22020 can be similar tothe tissue thickness compensator 10020, for example, in many respects.Further to the above, the firing member 10052 can include a cuttingportion 10053 which can be configured to transect the tissue positionedbetween the anvil 10060 and the tissue thickness compensator 22020 asthe firing member 10052 is advanced distally. In various circumstances,as a result, the firing member 10052 can be configured to concurrentlyfire the staples 22030 to staple the tissue T and cut the tissue T. Incertain circumstances, the firing process can at least partially leadthe cutting process. Stated another way, the cutting process can lag thefiring process. In such circumstances, a portion of the tissue T can bestapled and then incised.

As illustrated in FIGS. 9-12, the cartridge body 22010 can include acartridge knife slot 22015 which can be configured to receive a portionof the firing member 10052 as the firing member 10052 is advanceddistally. Further to the above, the anvil 10060 can include an anvilknife slot 10065 which can be configured to receive a portion of thefiring member 10052 as the firing member 10052 is advanced distally. Invarious circumstances, the tissue thickness compensator 22020 cancomprise a tissue thickness compensator knife slot 22025 which can bealigned with the anvil knife slot 10065 and the cartridge knife slot22015 such that the firing member 10052 can pass through the cartridgeknife slot 22015, the anvil knife slot 10065, and the tissue thicknesscompensator knife slot 22025 simultaneously. In various circumstances,the anvil knife slot 10065 can extend over the tissue thicknesscompensator knife slot 22025 such that the cutting portion 10053 of thefiring member 10052 can pass through the cartridge knife slot 22015, theanvil knife slot 10065, and the tissue thickness compensator knife slot22025 simultaneously. The tissue thickness compensator knife slot 22025can define a tissue thickness compensator knife path for the cuttingportion 10053 wherein the tissue thickness compensator knife path can beparallel to the anvil knife path and the cartridge knife path. Invarious circumstances, the tissue thickness compensator knife path canbe longitudinal while, in certain circumstances, the tissue thicknesscompensator knife path can be curved. Further to the above, curved endeffectors and curved fastener cartridges are disclosed in U.S. PatentApplication Publication No. 2008/0169329. The entire disclosure of U.S.patent application Ser. No. 11/652,164, entitled CURVED END EFFECTOR FORA SURGICAL STAPLING DEVICE, filed on Jan. 11, 2007, now U.S. PatentApplication Publication No. 2008/0169329, is hereby incorporated byreference herein. In such circumstances, a tissue thickness compensatorcan be curved. In at least one such embodiment, the tissue thicknesscompensator can be curved to match the curvature of the cartridge bodyof the fastener cartridge. Methods and techniques for modifying a tissuethickness compensator to include a knife slot such as, for example, theknife slot 22025 are described below.

Further to the above, referring primarily to FIG. 9, the tissuethickness compensator knife slot 22025 can extend between a firststapling portion 22021 a which can be stapled by a first group ofstaples 22030 and a second stapling portion 22021 b which can be stapledby a second group of staples 22030. The knife slot 22025 can releasablyconnect the first stapling portion 22021 a to the second staplingportion 22021 b. In use, as illustrated in FIG. 9, the cutting portion10053 can be advanced distally through the knife slot 22025 to transectthe knife slot 22025 and separate the first stapling portion 22021 a andthe second stapling portion 22021 b. In certain circumstances, the knifeslot 22025 can comprise a plurality of connectors, or bridges, 22026which can connect the first stapling portion 22021 a and the secondstapling portion 22021 b prior to being transected by the cuttingportion 10053. In various circumstances, the connectors 22026 can havethe same thickness as the first stapling portion 22021 a and/or thesecond stapling portion 22021 b, at least when the tissue thicknesscompensator 22020 is in an uncompressed state. In at least one suchcircumstance, the connectors 22026, the first stapling portion 22021 a,and/or the second stapling portion 22021 b can be unitarily andintegrally formed from a flat, or at least substantially flat, piece ofmaterial, for example. In various other circumstances, the firststapling portion 22021 a can comprise a first thickness, the secondstapling portion 22021 b can comprise a second thickness, and theconnectors 22026 can comprise a third thickness, wherein one or more ofthe first thickness, the second thickness, and the third thickness canbe different than the other thicknesses.

The knife slot 22025 can further comprise apertures, such as apertures22024, for example, defined therein. For instance, the apertures 22024can be elongate and can extend longitudinally along the knife slot22025. In various other circumstances, the apertures in the knife slot22025 can comprise any suitable arrangement. In certain circumstances,the apertures 22024 can comprise perforations positioned intermediatethe connectors 22026 which can be formed utilizing a laser cuttingoperation, for example. In some circumstances, the apertures 22024 canbe cut from a sheet of material to form the tissue thickness compensator22020 such that the apertures 22024 and the connectors 22026 arearranged in an alternating arrangement, for example. In other instances,the tissue thickness compensator 22020 can be molded with apertures22024 already formed therein. In various circumstances, one or more ofthe apertures 22024 can comprise through holes, for example. In variouscircumstances, one or more of the apertures 22024 can comprise clearanceapertures, for example. In certain instances, one or more of theapertures 22024 may not comprise through holes and may instead comprisereductions in the thickness of the knife slot 22025, for example.Methods and techniques for modifying a tissue thickness compensator toinclude apertures such as, for example, the apertures 22024 aredescribed below.

Further to the above, referring again to FIGS. 9-11, patient tissue canbe positioned intermediate the anvil 10060 of the end effector 22090 andthe tissue thickness compensator 22020 of the cartridge assembly 22000when the anvil 10060 is in an open position. When the anvil 10060 ismoved into a closed position, a bottom surface, or tissue-contactingsurface, 10063 of the anvil 10060 can contact the tissue T and push thetissue T toward a deck surface 22011 of the cartridge body 22010. Thetissue T can contact a top surface, or tissue contacting surface, 22021of the tissue thickness compensator 22020 wherein, when the anvil 10060is moved into its closed position, the anvil 10060 can press the tissueT against the tissue thickness compensator 22020 and, further to theabove, compress the tissue thickness compensator 22020 against the decksurface 22011 of the cartridge body 22010. In various circumstances, thetissue thickness compensator 22020 can comprise a bottom surface 22029which can abut the deck surface 22011. In some circumstances, a gap maybe present between the bottom surface 22029 and the deck surface 22011before the tissue thickness compensator 22020 is compressed against thecartridge body 22010. In such circumstances, the tissue thicknesscompensator 22020 may first translate toward the cartridge body 22010before being compressed thereagainst. When the tissue thicknesscompensator 22020 is compressed against the cartridge body 22010, invarious circumstances, the first stapling portion 22021 a and/or thesecond stapling portion 22021 b of the tissue thickness compensator22020 may move laterally. For instance, the first stapling portion 22021a and/or the second stapling portion 22021 b may move laterally awayfrom the cartridge knife slot 22015. In various circumstances, theconnectors 22026 can be configured to inhibit such lateral movementbetween the first stapling portion 22021 a and the second staplingportion 22021 b. In various circumstances, referring primarily to FIG.11, the connectors 22026 can be configured to stretch to permit somerelative lateral movement between the first stapling portion 22021 a andthe second stapling portion 22021 b when the anvil 10060 is closed. Inthe event that the anvil 10060 is reopened, the connectors 22026 can beconfigured to elastically return, or at least substantially return, totheir unstretched configuration and, as a result, pull the firststapling portion 22021 a and the second stapling portion 22021 blaterally back toward their original positions, illustrated in FIG. 10.Moreover, the anvil 10060 can compress the tissue T when the anvil 10060is moved into its closed position. In such circumstances, the tissue Tmay at least partially flow into the apertures 22024.

Upon reviewing FIGS. 10-12, the reader will appreciate that the knifeslot 22025 of the tissue thickness compensator 22020 comprises lessmaterial along the longitudinal length thereof than the first staplingportion 22021 a and/or the second stapling portion 22021 b. Statedanother way, a longitudinal cross-section through the first staplingportion 22021 a and/or the second stapling portion 22021 b wouldtransect a first amount of material while a longitudinal cross-sectionthrough the knife slot 22025 would transect a second amount of materialwhich is less than the first amount of material.

Once the anvil 10060 has been suitably positioned, further to the above,the firing member 10052 can be advanced distally to fire the staples, asillustrated in FIG. 11, and incise the tissue T and the connectors22026, as illustrated in FIG. 12. Furthermore, the tissue thicknesscompensator incision force, the tissue incision force, the tissuethickness compensator drag force, and/or the tissue drag force can dullthe cutting portion 10053 of the firing member 10052. A dull knife maynot be able to transect the tissue T and/or the tissue thicknesscompensator 22020, for example, according to a preferred manner. Withprimary reference to FIG. 12, the cutting portion 10053 can comprise afirst knife edge zone 10053 a, a second knife edge zone 10053 b, and/ora third knife edge zone 10053 c, for example, wherein the first knifeedge zone 10053 a is positioned vertically above the second knife edgezone 10053 b, and wherein the second knife edge zone 10053 b ispositioned vertically above the third knife edge zone 10053 c, forexample. The cutting portion 10053 can comprise any suitable numberand/or location of knife edge zones wherein the knife edge zonesdepicted in FIG. 12 have been selected for the purposes of discussion.Further to the above, the first knife edge zone 10053 a can beconfigured to transect the tissue T while the second knife edge zone10053 b can be configured to transect the tissue thickness compensator22020. As a result, the first knife edge zone 10053 a may experience thetissue incision force and/or the tissue drag force discussed above. Suchforces may wear or dull the first knife edge zone 10053 a at a firstrate. The second knife edge zone 10053 b may experience the tissuethickness compensator incision force and/or the tissue thicknesscompensator drag force discussed above. Such forces may wear or dull thesecond knife edge zone 10053 b at a second rate. In variouscircumstances, the second rate can be different than the first rate.

Turning now to FIGS. 13 and 14, a fastener cartridge 22400 can comprisea tissue thickness compensator 22420 which can include a first staplingportion 22421 a and a second stapling portion 22421 b which areconnected by a knife slot 22425. The knife slot 22425 can comprise anangled longitudinal connector 22426. The angled longitudinal connector22426 can extend between a proximal end 22401 of the knife slot 22425and a distal end 22402 of the knife slot 22425. In some circumstances,the angled longitudinal connector 22426 can extend the entire length ofthe knife slot 22425 while, in other circumstances, the angledlongitudinal connector 22426 can extend less than the length of theknife slot 22425. The angled longitudinal connector 22426 can extendbetween a top surface 22428 of the tissue thickness compensator 22420and a bottom surface 22429 of the tissue thickness compensator 22420. Insome circumstances, the angled longitudinal connector 22426 can extendthe entire distance between the top surface 22428 and the bottom surface22429 while, in other circumstances, the angled longitudinal connector22426 can extend less than the distance between the top surface 22428and the bottom surface 22429. In various circumstances, the proximal endof the longitudinal connector 22426 can extend from the top surface22428 of the tissue thickness compensator while the distal end of thelongitudinal connector 22426 can extend from the bottom surface 22429.Alternatively, the distal end of the longitudinal connector 22426 canextend from the top surface 22428 of the tissue thickness compensatorwhile the proximal end of the longitudinal connector 22426 can extendfrom the bottom surface 22429. In various circumstances, thelongitudinal connector 22426 can comprise a thin bridge (i.e. less thanthe full thickness of the tissue thickness compensator 22420) or aseries of thin bridges that join the first stapling portion 22421 awhich can be stapled by a first group of staples 22030 to the secondstapling portion 22421 b which can be stapled by a second group ofstaples 22030, for example. These thin, angled bridges, and/or thelongitudinal connector 22426, could distribute the wear across thesecond knife edge zone 10053 b, rather than concentrating it on onespot. In various circumstances, as a result, the wear occurring on thesecond knife edge zone 10053 b may be equal to, or closer to being equalto, the wear occurring at the first knife edge zone 10053 a, forexample.

Referring now to FIGS. 15-17, an exemplary tissue thickness compensatorassembly 1000 may include a first layer 1002 and a second layer 1004attachable to the first layer 1002. The tissue thickness compensatorassembly 1000 can be utilized with a surgical instrument such as, forexample, the surgical instrument 8010 (FIG. 1). In addition, the tissuethickness compensator assembly 1000 can be utilized in a similar manneras and can replace the tissue thickness compensator 22020 of thecartridge assembly 22000 of the end effector 22090 (FIG. 9). Forexample, the second layer 1004 of the tissue thickness compensatorassembly 1000 may include a first portion 1006 which can be positionedon the deck surface 22011 on a first side of the cartridge knife slot22015 in a similar fashion to the first stapling portion 22021 a and asecond portion 1008 which can be positioned on the deck surface 22011 ona second side, opposite the first side, of the cartridge knife slot22015 in a similar fashion to the second stapling portion 22021 b (FIGS.9-11). In various instances, the first portion 1006 and the secondportion 1008 of the second layer 1004 can be spaced apart and maycomprise a gap 1010 therebetween which can comprise a knife path for thecutting portion 10053 of the firing member 10052 and may extend at leastpartially over the cartridge knife slot 22015 when the tissue thicknesscompensator assembly 1000 is assembled with the cartridge end effector22090. In certain instances, the first layer 1002 can be configured tocouple the first portion 1006 and the second portion 1008 and extend atleast partially over the gap 1010, as illustrated in FIG. 17, forexample.

In use, tissue T can be captured between the anvil 10060 and a tissuecontacting surface 1012 of the first layer 1002. As the firing member10052 is advanced, a first group of staples 20030 can be deployed tostaple the first portion 1006 and a second group of staples can bedeployed to staple the second portion 1008. The first and second groupsof staples can be configured to penetrate through a first deckcontacting surface 1007 and a second deck contacting surface 1009,respectively, of the second layer 1004, then through the tissuecontacting surface 1012 of the first layer, and then through thecaptured tissue T to contact the pockets 10062 of the anvil 10060.Furthermore, the advancement of the firing member 10052 can cause thecutting portion 10053 to be advanced distally through the gap 1010 ofthe tissue thickness compensator assembly 1000. The cutting portion10053 may transect the first layer 1002 while advancing through the gap1010 thereby separating the first portion 1006 and the second portion1008 of the second layer 1004.

Referring again to FIG. 17, the first layer 1002 of the tissue thicknesscompensator assembly 1000 may comprise a first height H1, the firstportion 1006 of the second layer 1004 may comprise a second height H2,and the second portion 1008 of the second layer 1004 may comprise athird height H3. In certain circumstances, as illustrated in FIG. 17,the second height H2 and the third height H3 can be the same orsubstantially the same. In other circumstances, the second height H2 canbe different from the third height H3. In certain circumstances, thefirst height H1 can be less than the second height H2 and/or the thirdheight H3, as illustrated in FIG. 17. The first layer 1002 of the tissuethickness compensator assembly 1000 may comprise a first density, thefirst portion 1006 of the second layer 1004 may comprise a seconddensity, and the second portion 1008 of the second layer 1004 maycomprise a third density. In certain circumstances, as illustrated inFIG. 17, the second density and the third density can be the same orsubstantially the same. In other circumstances, the second density canbe different from the third density and/or different from the firstdensity of the first layer 1002. The material compositions of the firstportion 1006 and the second portion 1008 can be the same, or at leastsubstantially the same. In other circumstances, the materialcompositions of the first portion 1006 and the second portion 1008 canbe different from each other and/or can be different from the materialcomposition of the first layer 1002.

As described above, repeated use of the cutting portion 10053 to cuttissue T and tissue thickness compensator material may dull the cuttingportion 10053. To slow the dulling process, it may be desirable toreduce the tissue thickness compensator material that is cut by thecutting portion 10053. An additional benefit can be a reduction in theforces needed to advance the firing member 10052 distally during afiring stroke. In order to reduce the dulling of the cutting portion10053, the first layer 1002 can be comprised, at least partially, of athin film, for example. In such circumstances, the first height H1 canbe significantly less than the second height H2 and the third height H3,as illustrated in FIG. 17. In certain circumstances, the first layer1002 may comprise a uniform, or substantially uniform, heighttherethrough, as illustrated in FIG. 17. In other circumstances, a gapbridging portion 1014 of the first layer 1002 may extend at leastpartially over the gap 1010 and may be thinner than the remainder of thefirst layer 1002. The cutting portion 10053 may transect the gapbridging portion 1014 of the first layer 1002 while advancing throughthe gap 1010 between the first portion 1006 and the second portion 1008of the second layer 1004 which may reduce the resistance experienced bythe cutting portion 10053 and/or slow the dulling of the cutting portion10053. In any event, the first layer 1002 can be configured to maintaina coupling engagement with the first portion 1006 and the second portion1008 of the second layer 1004 prior to being transected, and to presentthe cutting portion 10053 with a reduced resistance as the cuttingportion 10053 is advanced to transect the first layer 1002.

To further reduce the dulling of the cutting portion 10053 and/or reducethe resistance experienced by the cutting portion 10053, the gapbridging portion 1014 may comprise a perforated segment 1016 along theknife path defined by the gap 1010, as illustrated in FIG. 16. Theperforated segment 1016 can include a plurality of perforations 1018which can be cut into the first layer 1002 prior to the assembly of thefirst layer 1002 to the second layer 1004, for example. The perforations1018 can reduce the interaction between the cutting portion 10053 andthe first layer 1002 as the cutting portion 10053 is advanced throughthe knife path defined by the gap 1010, which may slow the dulling ofthe cutting portion 10053 and/or reduce the resistance experienced bythe cutting portion 10053.

In various circumstances, as described in greater detail below, thetissue thickness compensator assembly 1000 can be comprised of one ormore biocompatible materials. In certain circumstance, the first layer1002 can be comprised of a biocompatible buttress material and/orplastic material, such as polydioxanone (PDS) and/or polyglycolic acid(PGA), for example, and the second layer 1004 can be comprised of abioabsorbable foam material and/or a compressible haemostatic material,such as oxidized regenerated cellulose (ORC), for example. In certaincircumstances, the first layer 1002 can be a thin film comprising abioabsorbable material such as polyglycolic acid (PGA) which is marketedunder the trade name Vicryl, polylactic acid (PLA or PLLA),polydioxanone (PDS), polyhydroxyalkanoate (PHA), poliglecaprone 25(PGCL) which is marketed under the trade name Monocryl, polycaprolactone(PCL), and/or a composite of PGA, PLA, PDS, PHA, PGCL and/or PCL, forexample. In certain circumstances, the first portion 1006 and/or thesecond portion 1008 of the second layer 1004 can be comprised of alyophilized foam comprising polylactic acid (PLA) and/or polyglycolicacid (PGA), for example. In certain circumstances, the first portion1006 and/or the second portion 1008 of the second layer 1004 can becomprised of biocompatible foam which may comprise a porous, open cellfoam and/or a porous, closed cell foam.

Referring again to FIGS. 15 and 17, the first layer 1002 can be at leastpartially disposed over the second layer 1004 such that the second layer1004 may be positioned between the first layer 1002 and the deck surface22011 (FIG. 9) when the tissue thickness compensator assembly 1000 isassembled with the end effector 22090 (FIG. 9). In other circumstances,the first layer 1002 can be positioned beneath the first portion 1006and the second portion 1008 (not shown) such that the first layer 1002may be positioned between the second layer 1004 and the deck surface22011 (FIG. 9) when the tissue thickness compensator assembly 1000 isassembled with the end effector 22090 (FIG. 9). In any event, the firstlayer 1002 can be attached to a first contacting surface 1020 of thefirst portion 1006 and a second contacting surface 1022 of the secondportion 1008 of the second layer 1004. The first layer 1002 can beattached to the second layer 1004 via a thermal pressing processinvolving the application of heat and/or pressure, as described ingreater detail below. In other circumstances, the first layer 1002 canbe attached to the second layer 1004 by a biocompatible adhesivematerial such as a fibrin and/or protein hydrogel, for example. Othermeans for attaching the first layer 1002 to the second layer 1004 arecontemplated by the present disclosure.

Referring now to FIGS. 21 and 22, the first layer 1002 can be at leastpartially embedded into the first portion 1006 and/or the second portion1008 of the second layer 1004. In such circumstances, the tissuethickness compensator assembly 1000 can be prepared using a mold 1024,for example, as illustrated in FIG. 21. In various instances, an organicsolution comprising a polymer such as, for example, polylactic acid(PLA) and/or polyglycolic acid (PGA) can be poured into the mold 1024.The first layer 1002 can be immersed into the organic solution. Asillustrated in FIG. 22, a central shelf 1026 and a central beam 1027 ofa mold cover 1028 can trap the first layer 1002 therebetween to ensurethat the first layer 1002 remains immersed in the organic solution whichcan then be lyophilized using conventional lyophilization techniquesand/or any other suitable techniques, for example. Upon completion ofthe lyophilization process, and/or any other suitable process, the moldcover 1028 can be removed and the tissue thickness compensator assembly1000 can be recovered from the mold 1028.

As illustrated in FIG. 21, the first layer 1002 of the tissue thicknesscompensator 1000 can be partially positioned within the first portion1006 and the second portion 1008 of the second layer 1004. In certaincircumstances, the first layer 1002 can be partially positioned withinone of the first portion 1006 and the second portion 1008 and attachedto a top surface or a bottom surface of the other one of the firstportion 1006 and the second portion 1008.

In certain circumstances, the central beam 1027 and the shelf 1026 canat least partially extend along an axis that is parallel orsubstantially parallel to the first deck contacting surface 1007 and/orthe second deck contacting surface 1009 when the cover 1028 is in aclosed configuration with mold 1024, as illustrated in FIG. 22. In suchcircumstances, the first layer 1002 can be embedded into the firstportion 1006 and/or the second portion 1008 such that first layer 1002is positioned or substantially positioned in a parallel or substantiallyparallel relationship with the first deck contacting surface 1007 and/orthe second deck contacting surface 1009. In other circumstances,although not illustrated, the central beam 1027 and the shelf 1026 canat least partially extend along an axis that is at an oblique angle withthe first deck contacting surface 1007 and/or the second deck contactingsurface 1008 when the cover 1028 is in a closed configuration with mold1024. In such circumstances, the first layer 1002 can be embedded intothe first portion 1006 and/or the second portion 1008 such that firstlayer 1002 is positioned or substantially positioned at an oblique anglewith respect to the first deck contacting surface 1007 and/or the seconddeck contacting surface 1009. Other techniques for partially embeddingthe first layer 1002 into the first portion 1006 and/or the secondportion 1008 are contemplated by the present disclosure.

Referring now to FIGS. 18 and 19, a tissue thickness compensatorassembly 1033, which is similar in many respects to the tissue thicknesscompensator assembly 1000 and the tissue thickness compensator 20020, isillustrated. The tissue thickness compensator assembly 1033 can comprisethe first portion 1006 and the second portion 1008 which can be spacedapart and separably coupled together by a plurality of bridging membersor connectors 1030 which may extend across the gap 1010 between thefirst portion 1006 and the second portion 1008. In addition, some or allof the connectors 1030 of the tissue thickness compensator assembly 1033can be partially embedded into the first portion 1006 and the secondportion 1008, as illustrated in FIG. 19. Furthermore, some or all of theconnectors 1030 can comprise a first end positioned within the firstportion 1006, a second end positioned within the second portion 1008,and a gap bridging portion 1032 therebetween. The gap bridging portion1032 may extend across the gap 1010 between the first portion 1006 andthe second portion 1008, as illustrated in FIG. 19. The connectors 1030can be spaced apart along the length of the gap 1010 to separably couplethe first portion 1006 to the second portion 1008.

In certain circumstances, the connectors 1030 can be evenly distributedalong an axis extending along the gap 1010, as illustrated in FIG. 19.In other circumstances, although not illustrated, the connectors 1030can be unevenly distributed along the axis extending along the gap 1010.The cutting portion 10053 can be configured to transect the gap bridgingportions 1032 of the connectors 1030 as the cutting portion 10053 isadvanced between the first portion 1006 and the second portion 1008through the knife path defined by the gap 1010. Where the connectors1030 are unevenly distributed along the axis extending along the firstportion 1006 and the second portion, in at least one instance, theconnectors 1030 can be disposed in greater frequency and/or in closerproximity to each other at a distal segment of the gap 1010 than at aproximal segment of the gap 1010 such that the cutting portion 10053 mayexperience an increasing resistance as it is advanced along the knifepath defined by the gap 1010. In other circumstances, the connectors1030 can be disposed in greater frequency and/or in closer proximity toeach other at a proximal segment of the gap 1010 than at a distalsegment of the gap 1010 such that the cutting portion 10053 mayexperience a decreasing resistance as it is advanced along the knifepath defined by the gap 1010, for example.

In certain circumstances, the connectors 1030 can extend orsubstantially extend in a single plane which can be parallel orsubstantially parallel to the first deck contacting portion 1007 and/orthe second deck contacting portion 1009, as illustrated in FIG. 19. Inother circumstances, although not illustrated, the connectors 1030 canextend or substantially extend along a plurality of planes which can beparallel or substantially parallel to each other and/or to the firstdeck contacting portion 1007 and/or the second deck contacting portion1009.

Further to the above, some or all of the gap bridging portions 1032 ofthe connectors 1030 can be thinner than the remainder of theirrespective connectors 1030 to present the cutting portion 10053 with areduced resistance as the cutting portion 10053 is advanced to transectthe connectors 1030 while maintaining a coupling engagement with thefirst portion 1006 and the second portion 1008 of the second layer 1004.For example, some or all the connectors 1030 can comprise a dog-boneshape with thicker ends terminating within the first portion 1006 andthe second portion 1008 of the second layer 1004 and thinner centralportions extending therebetween. In certain circumstances, theconnectors 1030 can each be comprised of a piece of suture which may becomprised of bioabsorbable material such as polyglycolic acid (PGA)which is marketed under the trade name Vicryl, polylactic acid (PLA orPLLA), polydioxanone (PDS), polyhydroxyalkanoate (PHA), poliglecaprone25 (PGCL) which is marketed under the trade name Monocryl,polycaprolactone (PCL), and/or a composite of PGA, PLA, PDS, PHA, PGCLand/or PCL, for example.

Referring again to FIG. 18, the tissue thickness compensator assembly1033 can be prepared using a mold 1034. An organic solution comprising apolymer such as, for example, polylactic acid (PLA) and/or polyglycolicacid (PGA) can be poured into the mold 1034. The connectors 1030 can beimmersed into the organic solution. As illustrated in FIG. 18, one ormore of the connectors 1030 can each be trapped in one or more dedicatedslots 1040 on a central shelf 1036 by one or more beams 1039 extendingfrom a mold cover 1038 and configured for mating engagement with theslots 1040 when the mold cover 1038 is in a closed configuration withthe mold 1034 to ensure that the connectors 1030 remain immersed in theorganic solution. The slots 1040 can be sized to receive or at leastpartially receive the bridging portions 1032 which can be secured by thebeams 1039 when the mold cover 1038 is in the closed configuration withthe mold 1034. The ends of the connectors 1030 extending from the gapbridging portions 1032 may freely float in the organic solution.Alternatively, the ends of the connectors 1030 can be secured to sidesof the mold 1034, for example. In certain circumstances, the connectors1030 can be stretched in the organic solution between the sides of themold 1034. In other circumstances, the connectors 1030 can be looselyheld between the sides of the mold 1034 to extend through the organicsolution in a non-linear fashion, for example.

Further to the above, in various instances, the organic solution canthen be lyophilized using conventional lyophilization techniques and/orany other suitable techniques. Upon completion of the lyophilizationprocess, the mold cover 1036 can be removed and the tissue thicknesscompensator assembly 1033 can be recovered from the mold 1034. Asillustrated in FIG. 19, the resulting tissue thickness compensatorassembly 1033 includes connectors 1030 partially positioned within thefirst portion 1006 and the second portion 1008. Other techniques forpartially embedding the connectors 1030 into the first portion 1006and/or the second portion 1008 are contemplated by the presentdisclosure. The reader will appreciate that the connectors 1030 can bepositioned closer to or further away from the deck contacting surfaces1007 and 1009 by changing the height of the central shelf 1038 and/ordepth of the slots 1040.

Referring now to FIG. 20, a tissue thickness compensator assembly 1042,which may be similar in many respects to the tissue thicknesscompensator assembly 1033, the tissue thickness compensator assembly1000, and/or the tissue thickness compensator 20020, is illustrated. Thetissue thickness compensator assembly 1042 may comprise the firstportion 1006 and the second portion 1008 which can be spaced apart andseparably coupled together by a continuous flexible member 1044 whichmay form a plurality of bridging members or connectors 1046 which mayextend across the gap 1010 between the first portion 1006 and the secondportion 1008. The continuous flexible member 1044 may include a firstend 1048, a second end 1050, and a flexible portion 1052 extendingbetween the first end 1048 and the second end 1050. The flexible portion1052 can be configured to extend through the first portion 1006 and thesecond portion 1008 several times, for example in a zigzag pattern, toform the connectors 1046, as illustrated in FIG. 20. The flexibleportion 1052 can be passed in a first direction through a distal segment1054 of the first portion 1006 and a distal segment 1056 of the secondportion 1008 to form a first gap bridging portion 1046 a across the gap1010. The flexible portion 1052 can then be looped and passed in asecond direction, opposite the first direction, through the secondportion 1008 proximal to the distal segment 1056 and through the firstportion 1006 proximal to the distal segment 1054 thereby forming asecond gap bridging portion 1046 b proximal the first gap bridgingportion 1046 a. Additional gap bridging portions 1046 c and 1046 d, forexample, can be formed in the same manner across the gap 1010, asillustrated in FIG. 20.

In certain circumstances, the continuous flexible member 1044 cancomprise a suture and can be comprised of a suture material such aspolyglycolic acid (PGA) which is marketed under the trade name Vicryl,polylactic acid (PLA or PLLA), polydioxanone (PDS), polyhydroxyalkanoate(PHA), poliglecaprone 25 (PGCL) which is marketed under the trade nameMonocryl, polycaprolactone (PCL), and/or a composite of PGA, PLA, PDS,PHA, PGCL and/or PCL, for example. In certain circumstances, the tissuethickness compensator assembly 1042 can be assembled after the firstportion 1006 and the second portion 1008 are manufactured, for example,via lyophilization. In some circumstances, a needle (not shown) can beattached to the first end 1048 of the continuous flexible member 1044and can be passed through the first portion 1006 and the second portion1008, for example in a zigzag pattern, to couple the first portion 1006to the second portion 1008, as described above. The first end 1048and/or the second end 1050 of the continuous flexible member 1044 can besecured to the side walls of the first portion 1006 and/or the secondportion 1008 by tying in one or more knots at the first end 1048 and/orthe second end 1050, for example. The knots may abut against the sidewalls of the first portion 1006 and/or the second portion 1008 toprevent the flexible portion 1052 from unraveling relative to the firstportion 1006 and/or the second portion 1008. In other circumstances, thefirst portion 1006 and the second portion 1008 of the tissue thicknesscompensator assembly 1042 can be formed around the continuous flexiblemember 1044. In such circumstances, as illustrated in FIG. 20, thecontinuous flexible member 1044 can be disposed in a mold 1062, forexample in a zigzag pattern, with slots 1064 defined side walls 1066 andslots 1068 defined in central shelf 1070. An organic solution comprisinga polymer such as, for example, polylactic acid (PLA) and/orpolyglycolic acid (PGA) can be poured into the mold 1062 until thecontinuous flexible member 1044 is immersed in the organic solution. Amold cover 1072 can be used to ensure that the continuous flexiblemember 1044 remains immersed in the organic solution which can then belyophilized using conventional lyophilization techniques and/or anyother suitable techniques. The first end 1048 and the second end 1050 ofthe continuous flexible member 1044 can be secured at openings 1053 and1055 of the mold 1062, respectively, by tying in one or more knots atthe first end 1048 and the second end 1050 after passing the first end1048 through the opening 1053 and the second end 1050 through theopening 1055, for example. The knots may abut against the side walls ofthe mold 1062 to prevent the continuous flexible member 1044 fromunraveling relative to the mold 1066. After the tissue thicknesscompensator has been removed from the mold, in various instances,portions of the continuous flexible member 1044, such as portions 1048,1050, and/or 1052, for example, can then be cut and removed from thetissue thickness compensator. Other techniques for assembling the tissuethickness compensator assembly 1042 are contemplated by the presentdisclosure.

In certain circumstances, a tissue thickness compensator assembly suchas, for example, the tissue thickness compensator assembly 1042 can becompromised when excessive force or pressure is applied thereto. Forinstance, pressure can be applied to a tissue thickness compensatorassembly such as, for example, the tissue thickness compensator assembly1042 when the tissue thickness compensator assembly 1042 is loaded ontoa staple cartridge such as, for example, the staple cartridge 10000. Thetissue thickness compensator assembly 1042 can be equipped with apressure or force sensitive member that can provide a user with awarning feedback if the pressure experienced by the tissue thicknesscompensator assembly exceeds a threshold. For example, a pressure orforce sensitive film can be attached to the tissue thickness compensatorassembly 1042 and can be configured to change color upon experiencingpressure that exceeds the threshold. In certain circumstances, thepressure or force sensitive film can be disposed over the first portion1006 and/or the second portion 1008 and can be attached thereto via anadhesive, for example. The pressure or force sensitive film can bebiocompatible to permit implantation of the pressure or force sensitivefilm with the tissue thickness compensator assembly 1042 inside apatient.

Referring now to FIGS. 23-25, a surgical end effector 1100 isillustrated. The end effector 1100 is similar in many respects tovarious end effectors disclosed elsewhere herein such as, for example,the end effector 22090 (FIG. 9). As illustrated in FIG. 23, the endeffector 1100 can include a staple cartridge assembly 1102 which issimilar in many respects to the staple cartridge assembly 20200 (FIG.6), for example. In addition, the end effector 1100 may include a tissuethickness compensator 1104 which is similar in many respects to othertissue thickness compensators disclose elsewhere in this document suchas the tissue thickness compensator 22020 (FIG. 9), the tissue thicknesscompensator 20220 (FIG. 6), and/or the tissue thickness compensator10020 (FIG. 4), for example.

Further to the above, end effector 1100 can include a tissue thicknesscompensator 1104 wherein the tissue thickness compensator 1104 can beprepared using conventional lyophilization techniques and/or any othersuitable techniques. In at least one example, the tissue thicknesscompensator 1104 can be prepared by dissolving a polymer such as, forexample, polylactic acid (PLA) and/or polyglycolic acid (PGA) in anorganic solvent and lyophilizing the solution. The tissue thicknesscompensator 1104 can be comprised of a biocompatible foam which maycomprise a porous, open cell foam and/or a porous, closed cell foam, forexample.

Further to the above, the tissue thickness compensator 1104 can bealtered or modified for use in a surgical procedure. For example, uponcompletion of the lyophilization process, the tissue thicknesscompensator 1104 can be contacted with a modifying member 1106 to modifythe tissue thickness compensator 1104 for use in a particular surgicalprocedure. In certain circumstances, the modification can occur afterassembling the tissue thickness compensator 1104 with the end effector1100, as illustrated in FIGS. 23-35. For example, as illustrated in FIG.23, the tissue thickness compensator 1104 can be releasably assembled tothe cartridge assembly 1102 and modified while assembled with thecartridge assembly 1102. In other circumstances, the modification canoccur before assembling the tissue thickness compensator 1104 with theend effector 1100. In at least one example, the modification can beperformed as a separate step during manufacturing. In yet anotherexample, the modification may be performed during a surgical procedure.

As described in greater detail below, the modification process caninvolve modifying a surface or a plurality of surfaces of the tissuethickness compensator 1104. In certain circumstances, the modificationprocess can involve modifying one or more portions of the tissuethickness compensator 1104. One or more portions can be modified in asingle modification process. Alternatively, a plurality of portions caneach be modified separately in consecutive modification processes. Incertain circumstances, the modification process can comprise a thermalpressing process which can be used to change the shape, size,dimensions, and/or porosity of at least a portion of the tissuethickness compensator 1104. Furthermore, the modification process caninclude means for creating space within one or more portions of thetissue thickness compensator 1104.

Referring again to FIGS. 23-25, in certain circumstances, a portion 1107(FIG. 23) of the tissue thickness compensator 1104 can be modified by athermal pressing process which may include transitioning the portion1107 to a glassy state, engaging the portion 1107 with the modifyingmember 1106, applying pressure onto the portion 1107 while it is in theglassy state, and allowing the portion 1107 to cool below the glassystate while the modifying member 1106 is still engaged with the portion1107. The modifying member 1106 may be used to maintain the pressure onthe portion 1107 for a time period sufficient to create the resultingmodified portion 1108 (FIG. 25). It is note worthy that a material'stransition into a glassy state can be a reversible transition from arelatively hard state to a relatively molten or flexible state inresponse to an increase in the temperature of the material to a glasstransition temperature. A glass transition temperature of the materialcan be a particular temperature or, in some instances, a range oftemperatures. The tissue thickness compensator modification processdescribed herein takes advantage of this phenomenon by modifying atissue thickness compensator while the tissue thickness compensator isin the glassy flexible state and then allowing the tissue thicknesscompensator to cool below the glass transition temperature whilemaintaining the modification.

Further to the above, referring again to FIGS. 23-25, the portion 1107of the tissue thickness compensator 1004 can be transitioned into theglassy state by heating at least the portion 1107 to a temperaturegreater than or equal to a glass transition temperature of the materialfrom which the portion 1107 is composed but lower than the meltingtemperature of the same. For example, the tissue thickness compensator1104 can be comprised of polyglycolic acid (PGA) and in suchcircumstances, the portion 1107 can be transitioned into the glassystate by heating the portion 1107 to a temperature that is greater thanor equal to the glass transition temperature of polyglycolic acid (PGA)but lower than the melting temperature of the same. In variousinstances, the glass transition temperature of polyglycolic acid (PGA)can be in the range of 35-40° C., for example, and its meltingtemperature can be in the range of 225-230° C., for example. In at leastone example, the portion 1107 of the tissue thickness compensator 1104can be heated to a temperature that is greater than or equal to 35° C.but lower than 225° C. in order to transition the portion 1107 to theglassy state. In another example, the portion 1107 can be transitionedto the glassy state by heating the portion 1107 to a temperature that isgreater than or equal to 40° C. but lower than 200° C., for example.

Further to the above, the modifying member 1106 can then be used toapply pressure onto the portion 1107 while the portion 1107 is in theglassy state. The portion 1107 can be allowed to exit the glassy stateby cooling the portion 1107 to a temperature below 35° C., for example.The pressure may be maintained for a time period sufficient to permitthe tissue thickness compensator 1104 to retain, or at least partiallyretain, the modification imposed by the modifying member 1106.

In certain examples, the pressure can be maintained for a period of timefrom about 30 seconds to about 8 hours, for example, during the time inthe glassy state and/or for a period of time from about 30 seconds toabout 8 hours, for example, after exiting the glassy state. In at leastone example, the pressure can be maintained for approximately 10 minutesduring the time in the glassy state and for approximately 10 minutesafter exiting the glassy state. Other time periods for maintaining thepressure are contemplated by the present disclosure.

In certain circumstances, the modifying member 1106 can be used to applypressure onto the portion 1107 before the portion 1107 is transitionedto the glassy state. In certain circumstances, the modifying member 1106may apply pressure to the portion 1107 while the portion 1107 is heatedto reach the glassy state, while the portion 1107 is in the glassystate, and/or while the portion 1107 is transitioned or cooled to atemperature below the glassy state. In certain circumstances, thepressure applied to the portion 1107 can be gradually increased toward athreshold as the temperature of the portion 1107 is gradually increasedto transition the portion 1107 toward the glassy state, for example. Incertain circumstances, the pressure applied to the portion 1107 can beremoved, gradually removed, or at least partially reduced as the portion1107 exits the glassy state, before the portion 1107 exits the glassystate, and/or after the portion 1107 exits the glassy state.

In certain circumstances, the modifying member 1106 can also be a heatsource for transitioning the portion 1107 of the tissue thicknesscompensator 1104 to the glassy state. For example, the modifying member1106 can comprise a cylindrical distal portion 1110, as illustrated inFIG. 24, which may include a heating coil (not shown). A user can mayenergize the heating coil and engage the portion 1107 of the tissuethickness compensator 1104 with the modifying member 1106 to heat theportion 1107 to a temperature that is greater than or equal the glasstransition temperature of the material composition of the portion 1107.Upon reaching a desired temperature, the modifying member may be pressedagainst the portion 1107, as illustrated in FIG. 24. Alternatively, themodifying member may be pressed against the portion 1107 before themodifying member 1106 reaches the desired temperature. As describedabove, the pressure may be maintained for a time period sufficient topermit the tissue thickness compensator 1104 to retain, or at leastpartially retain, the modification imposed by the modifying member 1106.In addition, the heating coil of the modifying member 1106 can be turnedoff to allow the temperature of the portion 1107 to cool below the glasstransition temperature. The modifying member can then be removed. Incertain circumstances, the pressure applied by the modifying member 1106can be initiated prior to the portion 1107 entering the glassy state andmaintained throughout the glassy state. In some circumstances, thepressure applied by the modifying member 1106 can be removed while theportion 1107 is in the glassy state.

As illustrated in FIGS. 23-25, the modifying member 1106 can beconfigured to change the shape, size, dimensions, density, spring rate,and/or porosity of the portion 1107 of the tissue thickness compensator1104. For example, the modified portion 1108 may comprise asubstantially concave top surface 1114 with a reduced height H1, whilethe remainder of the tissue thickness compensator 1104 may retain asubstantially flat top surface including an original height H which isgreater than the reduced height H1, as illustrated in FIG. 25. Asdescribed above, the modifying member 1106 may comprise a cylindricaldistal portion 1110. In such circumstances, the curvature of theresulting concave surface 1114 can, in part, depend on the curvature ofthe cylindrical distal portion 1110 of the modifying member 1106 incontact with the portion 1107 of the tissue thickness compensator 1104during the modification process. Furthermore, the modified portion 1108may possess a new lower porosity compared to the unmodified portion 1107which can result, at least in part, from the compressive forces appliedto the portion 1107 by the modifying member 1106 during the modificationprocess, as described above. Said another way, the pressure applied tothe portion 1107 during the modification process may yield a materialredistribution wherein a cross-section through the modified portion 1108may comprise a greater material density than a similar cross sectionthrough the portion 1107 prior to the modification process. Furthermore,the modified portion 1108 may comprise a different spring rate from theremainder of the tissue thickness compensator 1104 which can result, inpart, from the changes in density and porosity realized by the modifiedportion 1108 during the modification process, as described in greaterdetail below. In at least one instance, the spring rate of the modifiedportion 1108 may be less than or greater than the spring rate of theunmodified portion 1107.

Referring now to FIGS. 26-34, a tissue thickness compensator can bemodified prior to assembly with an end effector such as, for example,the end effector 22090 (FIG. 9). In certain circumstances, asillustrated in FIGS. 27, 30, and 33, a mold can be utilized to modify atissue thickness compensator using a thermal pressing process, asdescribed above. For example, as illustrated in FIGS. 26-28, a tissuethickness compensator 1120 can be modified to include a longitudinalslot 1122. The tissue thickness compensator 1120 may be similar in manyrespects to other tissue thickness compensators described elsewhere suchas, for example, the tissue thickness compensator 22020 (FIG. 9). Forexample, like the compensator 22020, the compensator 1120 can beutilized with the end effector 22090. Furthermore, the longitudinal slot1122 may be similar in many respects to the knife slot 22025. Forexample, like the knife slot 22025, the slot 1122 may define a tissuethickness compensator knife path for the cutting portion 10053 between afirst stapling portion 1124 a and a second stapling portion 1124 b.Furthermore, the first stapling portion 1124 a and the second staplingportion 1124 b can be similar in many respects to the first staplingportion 22021 a (FIG. 9) and the second stapling portion 22021 b (FIG.9), respectively, of the tissue thickness compensator 22020. Inaddition, the slot 1122 can be configured to releasably connect thefirst stapling portion 1124 a and the second stapling portion 1124 bsuch that, in use with the end effector 22090, the cutting portion 10053can be advanced distally through the slot 1122 to transect the slot 1122and separate the first stapling portion 1124 a and the second staplingportion 1124 b.

Referring again to FIGS. 26-28, the tissue thickness compensator 1120can be prepared using traditional lyophilization techniques and/or anyother suitable techniques. In addition, the tissue thickness compensator1120 can be modified or altered to create the slot 1122 therethroughSimilar to the tissue thickness compensator 1104, the tissue thicknesscompensator 1120 can be comprised at least in part of a materialcomprising a glass transition temperature and can modified bytransitioning the material into a glassy state. In one example, thetissue thickness compensator 1120 can be heated in an oven (not shown)to a temperature greater than or equal to the glass transitiontemperature of the material composition of the tissue thicknesscompensator 1120 but less than the melting temperature of the same. Amold 1126 comprising a central beam 1128, as illustrated in FIG. 27, canbe utilized to create the slot 1122 by inserting the central beam 1128into the tissue thickness compensator 1120 while the tissue thicknesscompensator 1120 is in the glassy state. The tissue thicknesscompensator 1120 can then be allowed to cool to a temperature below theglass transition temperature while the central beam 1128 remainsinserted into the tissue thickness compensator 1120. In some instances,the central beam 1128 can be removed from the tissue thicknesscompensator 1120 while the tissue thickness compensator 1120 is in itsglassy state.

In certain circumstances, a cooling medium can be utilized to activelycool the tissue thickness compensator 1120. In some instances, a fan canbe used to generate a flow of air over the tissue thickness compensator1120 while the tissue thickness compensator 1120 is in the mold 1126and/or after the tissue thickness compensator 1120 has been removed fromthe mold. In some instances, a refrigeration process can be utilized tocool the tissue thickness compensator 1120 while the tissue thicknesscompensator 1120 is in the mold 1126 and/or after the tissue thicknesscompensator 1120 has been removed from the mold. The central beam 1128can be removed after transitioning the tissue thickness compensator 1120out of the glassy state. The central beam 1128 can remain inserted intothe tissue thickness compensator 1120 for a time period sufficient topermit the tissue thickness compensator 1120 to retain, or at leastsubstantially retain, the space occupied by the central beam 1128. Incertain examples, the central beam 1128 can remain inserted for a periodof time from about 30 seconds to about 8 hours, for example, during thetime in the glassy state and/or for a period of time from about 30seconds to about 8 hours, for example, after exiting the glassy state.In at least one example, the central beam 1128 can remain inserted forapproximately 10 minutes during the time in the glassy state and forapproximately 10 minutes after exiting the glassy state. Other timeperiods for maintaining the central beam 1128 within the tissuethickness compensator 1120 are contemplated by the present disclosure.

Further to the above, as illustrated in FIG. 28, pressure applied by thecentral beam 1128 during the modification process may yield an increasedmaterial density at a portion 1130 of the tissue thickness compensator1120. The portion 1130 may connect the first stapling portion 1124 a anda second stapling portion 1124 b thereby providing additional stabilityfor the slot 1122. In certain circumstances, the mold 1126 may compriseedge modifiers such as, for example, edge modifiers 1132 a and 1132 bwhich can modify the tissue thickness compensator 1120 during themodification process to produce modified edges 1134 a and 1134 b,respectively, as illustrated in FIG. 28.

Referring again to FIGS. 26-28, it may be desirable to remove asignificant amount of material from the tissue thickness compensator1120 to create the slot 1122. In such circumstances, the central beam1128 can be heated to a temperature greater than the melting temperatureof the material composition of the tissue thickness compensator 1120.Upon inserting the heated central beam 1128 into the tissue thicknesscompensator 1120, the central beam 1128 may melt through the tissuethickness compensator 1120 thereby creating a space for the slot 1122within the tissue thickness compensator 1120, as illustrated in FIG. 28.In certain circumstances, it may be desirable to gradually increase thepressure applied by the central beam 1128 against the tissue thicknesscompensator 1120 to gradually insert the central beam 1128 into thetissue thickness compensator 1120.

In certain circumstances, it can be desirable to increase materialdensity of one or more surfaces of a tissue thickness compensator. Asillustrated in FIGS. 29-31, a tissue thickness compensator 1140 can bemodified or altered such that a surface 1142 of the tissue thicknesscompensator 1140 may comprise a higher material density than theremainder of the tissue thickness compensator 1140, which can beachieved, in certain circumstances, post lyophilization. The tissuethickness compensator 1140 may be similar in many respects to othertissue thickness compensators described elsewhere such as, for example,the tissue thickness compensator 22020 (FIG. 9) and/or the tissuethickness compensator 1120 (FIG. 26). A surface modifier 1144 can beutilized to modify the surface 1142 of the tissue thickness compensator1140 using a thermal pressing process which is similar in many respectsto the thermal pressing processes used to modify the tissue thicknesscompensator 1104 and/or the tissue thickness compensator 1120, asdescribed above. For example, the tissue thickness compensator 1140 canbe comprised at least in part of a material comprising a glasstransition temperature and can be modified after being transitioned intoa glassy state.

As described above, a tissue thickness compensator such as, for example,the tissue thickness compensator 1140 can be transitioned to the glassystate where it is heated to a temperature greater than or equal to theglass transition temperature of the material composition of the tissuethickness compensator 1140 but less than the melting temperature of thesame. The surface modifier 1144 can be pressed against the surface 1142while the tissue thickness compensator 1140 is in the glassy state. Thepressure applied by the surface modifier 1144 may compress the surface1142 thereby increasing the material density of the surface 1142. Theincrease in material density can be retained by the surface 1142 byallowing the surface 1142 to cool to a temperature below the glasstransition temperature.

In certain instances, the pressure applied by the surface modifier 1144against the surface 1142 can be maintained for a period of time fromabout 30 seconds to about 8 hours, for example, during the time in theglassy state and/or for a period of time from about 30 seconds to about8 hours, for example, after exiting the glassy state. In at least oneexample, the pressure can be maintained for approximately 10 minutesduring the time in the glassy state and for approximately 10 minutesafter exiting the glassy state. Other time periods for maintaining thepressure applied by the surface modifier 1144 against the surface 1142are contemplated by the present disclosure.

In some instances, a fan can be used to generate a flow of air over thetissue thickness compensator 1140 while the tissue thickness compensator1140 is in contact with the modifier 1144 and/or after the tissuethickness compensator 1140 has been removed from the modifier 1144. Insome instances, a refrigeration process can be utilized to cool thetissue thickness compensator 1140 while the tissue thickness compensator1140 is in contact with the modifier 1144 and/or after the tissuethickness compensator 1140 has been removed from the modifier 1144. Upontransitioning the tissue thickness compensator 1140 out of the glassystate, in various instances, the surface modifier 1144 can be disengagedfrom the tissue thickness compensator 1140. In certain circumstances,the surface modifier 1144 can include a heating element which can beutilized to increase the temperature of the surface 1142 to atemperature greater than or equal to the glass transition temperature ofthe material composition of the tissue thickness compensator 1140, asdescribed above.

Referring again to FIG. 30, the surface modifier 1144 may comprise aflat, or at least substantially flat, contacting surface 1146 forcontacting the surface 1142, for example. In other circumstances, thecontacting surface 1146 may comprise various textures such as, forexample, protrusions which can extend into the surface 1142 of thetissue thickness compensator 1140 during the modification process. Incertain circumstances, the surface modifier 1144 can be used to applypressure onto the surface 1142 of the tissue thickness compensator 1140before the tissue thickness compensator 1140 is transitioned to theglassy state. In certain circumstances, the surface modifier 1144 mayapply pressure to the surface 1142 while the tissue thicknesscompensator 1140 is heated to reach the glassy state, while the tissuethickness compensator 1140 is in the glassy state, and/or while thetissue thickness compensator 1140 is transitioned or cooled to atemperature below the glassy state. In certain circumstances, thepressure applied by the surface modifier 1144 to the surface 1142 can begradually increased toward a threshold as the temperature of the tissuethickness compensator 1140 is gradually increased to transition thetissue thickness compensator 1140 toward the glassy state, for example.In certain circumstances, the pressure applied to the surface 1142 canbe removed, gradually removed, or at least partially reduced as thetissue thickness compensator 1140 exits the glassy state, before thetissue thickness compensator 1140 exits the glassy state, and/or afterthe tissue thickness compensator 1140 exits the glassy state.

In certain circumstances, the tissue thickness compensator 1140 can bemodified or altered to include a skin or a dense outer layer. In certaincircumstances, the resulting skin or dense outer layer may comprisetextures such as, for example, protrusions which can extend into thesurface 1142 of the tissue thickness compensator 1140. In certaininstances, the contacting surface 1146 of the surface modifier 1144 canbe heated to a temperature greater than or equal to the meltingtemperature of the material composition of the tissue thicknesscompensator 1140. The surface modifier 1144 and/or the tissue thicknesscompensator 1140 can be moved to bring the surface 1142 of the tissuethickness compensator 1140 into contact with the heated contactingsurface 1146 of the surface modifier 1144 thereby melting, or at leastsubstantially melting, the surface 1142. The surface modifier 1144 andthe tissue thickness compensator 1140 can then be separated to permitthe modified surface 1142 to cool below its melting temperature whichmay create a skin or a dense outer layer onto the tissue thicknesscompensator 1140.

In certain instances, the contacting surface 1146 of the surfacemodifier 1144 can be heated prior to coming in contact with the surface1142. In other instances, the contacting surface 1146 of the surfacemodifier 1144 can be heated after coming in contact with the surface1142.

In certain instances, the contacting surface 1146 of the surfacemodifier 1144 can remain in contact with the surface 1142 of the tissuethickness compensator 1140 for a time period sufficient to allow thesurface 1142 to flow into a desired geometry. Such a time period canrange from about 30 seconds to about 8 hours, for example; other timeperiods are contemplated by the present disclosure. Such a time periodcan be sufficient to locally affect and/or melt the material of thetissue thickness compensator 1140 and have it flow into a new geometry.As described herein, such a new geometry can be prescribed by thetooling used to make the tissue thickness compensator 1140.

In certain instances, the surface 1142 of the tissue thicknesscompensator 1140 can be allowed to cool, or can be actively cooled, to atemperature below the melting temperature of the tissue thicknesscompensator 1140 before separating the surface modifier 1144 from thetissue thickness compensator 1140. In other instances, the surface 1142of the tissue thickness compensator 1140 can be allowed to cool, or canbe actively cooled, to a temperature below the melting temperature ofthe tissue thickness compensator 1140 after separating the surfacemodifier 1144 from the tissue thickness compensator 1140.

Further to the above, the modified surface 1142 can comprise a densitywhich is approximately 10% greater than the density of the remainder ofthe tissue thickness compensator 1140, approximately 20% greater thanthe density of the remainder of the tissue thickness compensator 1140,approximately 30% greater than the density of the remainder of thetissue thickness compensator 1140, approximately 40% greater than thedensity of the remainder of the tissue thickness compensator 1140,approximately 50% greater than the density of the remainder of thetissue thickness compensator 1140, approximately 60% greater than thedensity of the remainder of the tissue thickness compensator 1140,approximately 70% greater than the density of the remainder of thetissue thickness compensator 1140, approximately 80% greater than thedensity of the remainder of the tissue thickness compensator 1140,approximately 90% greater than the density of the remainder of thetissue thickness compensator 1140, and/or approximately 100% greaterthan the density of the remainder of the tissue thickness compensator1140, for example. In various circumstances, the modified surface 1142can comprise a density which is more than the density of the remainderof the tissue thickness compensator 1140 and less than twice the densityof the remainder of the tissue thickness compensator 1140, for example.In various circumstances, the modified surface 1142 can comprise adensity which is over twice the density of the remainder of the tissuethickness compensator 1140, for example.

Referring now to FIGS. 32-34, a tissue thickness compensator 1150 can bemodified to include a plurality of apertures 1152 which may extend atleast partially through the tissue thickness compensator 1150. Thetissue thickness compensator 1150 may be similar in many respects toother tissue thickness compensators described herein such as, forexample, the tissue thickness compensator 20220 (FIG. 6). Like thecompensator 20220, the compensator 1150 can be utilized with thecartridge assembly 20200 (FIG. 6) and the apertures 1152 may be similarin many respects to the clearance apertures 20224 extending at leastpartially through the tissue thickness compensator 20220. For example,like the apertures 20224, the apertures 1152 can be aligned withcorresponding staple legs 20232 (FIG. 7) when the tissue thicknesscompensator 1150 is assembled with the cartridge assembly 20200 suchthat the staple legs 20232 may move through the clearance apertures 1152in the tissue thickness compensator 1150 when the staple legs 20232 movefrom the unfired configuration to the fired configuration, as describedabove in greater detail.

Further to the above, referring again to FIGS. 32-34, the tissuethickness compensator 1150 can be prepared using traditionallyophilization techniques and/or any other suitable techniques. Incertain circumstances, a polymer having a glass transition temperaturesuch as, for example, polylactic acid (PLA) and/or polyglycolic acid(PGA) can be dissolved in an organic solvent to form a solution whichcan be lyophilized to produce the tissue thickness compensator 1150.Furthermore, the tissue thickness compensator 1150 can be modified postlyophilization using a thermal pressing process which is similar in manyrespects to the thermal pressing processes used to modify the tissuethickness compensator 1104, the tissue thickness compensator 1120,and/or the tissue thickness compensator 1140, for example, as describedabove. For example, the tissue thickness compensator 1150 can bemodified to include the apertures 1152 once the tissue thicknesscompensator 1150 is transitioned to a glassy state.

As described above, a tissue thickness compensator such as, for example,the tissue thickness compensator 1150 can be transitioned to a glassystate by being heated in an oven (not shown) to a temperature greaterthan or equal to the glass transition temperature of the materialcomposition of the tissue thickness compensator 1150 but less than themelting temperature of the same. A mold 1154 comprising a plurality ofposts, dowels, pins, and/or protrusions, for example, such as, forexample, needles 1156 can be utilized to create the apertures 1152 byinserting the needles 1156 into the tissue thickness compensator 1150while the tissue thickness compensator 1150 is in the glassy state. Thetissue thickness compensator 1150 can then be allowed to cool to atemperature below the glass transition temperature while the needles1156 remain inserted into the tissue thickness compensator 1150. In someinstances, the needles 1156 can be removed from the tissue thicknesscompensator 1150 while the tissue thickness compensator 1150 is in theglassy state. In some instances, a fan can be used to generate a flow ofair over the tissue thickness compensator 1150 while the tissuethickness compensator 1150 is engaged with the needles 1156 and/or afterthe tissue thickness compensator 1150 has been disengaged from theneedles 1156. In some instances, a refrigeration process can be utilizedto cool the tissue thickness compensator 1150 while the tissue thicknesscompensator 1150 is engaged with the needles 1156 and/or after thetissue thickness compensator 1150 has been disengaged from the needles1156. In various instances, the needles 1156 can be removed aftertransitioning the tissue thickness compensator 1150 out of the glassystate. The needles 1156 can remain inserted into the tissue thicknesscompensator 1150 for a time period sufficient to permit the tissuethickness compensator 1150 to retain, or at least substantially retain,the spaces defining the apertures 1152 which are occupied by the needles1156.

In certain examples, the needles 1156 can remain inserted for a periodof time from about 30 seconds to about 8 hours, for example, during thetime in the glassy state and/or for a period of time from about 30seconds to about 8 hours, for example, after exiting the glassy state.In at least one example, the needles 1156 can remain inserted forapproximately 10 minutes during the time in the glassy state and forapproximately 10 minutes after exiting the glassy state. Other timeperiods for maintaining the needles 1156 inserted into the tissuethickness compensator 1150 are contemplated by the present disclosure.

In certain circumstances, the needles 1156 can be removed from thetissue thickness compensator 1150 prior to transitioning the tissuethickness compensator 1150 out of the glassy state. In othercircumstances, the needles 1156 can be gradually removed over time. Forexample, the needles 1156 can be partially removed from the tissuethickness compensator 1150 prior to transitioning the tissue thicknesscompensator 1150 out of the glassy state. The needles 1156 can then befully removed from the tissue thickness compensator 1150 aftertransitioning the tissue thickness compensator 1150 out of the glassystate. The reader will appreciate that the greater the depth ofinsertion of the needles 1156 into the tissue thickness compensator1150, the greater the depth of the corresponding apertures 1152 that canbe created in the tissue thickness compensator 1150.

Referring again to FIGS. 32-34, in certain instances, the needles 1156can be heated to a temperature greater than or equal to the meltingtemperature of the material composition of the tissue thicknesscompensator 1150. In addition, the needles 1156 can be inserted into thetissue thickness compensator 1150 to create the apertures 1152 bymelting, or at least partially melting, through the regions of thetissue thickness compensator 1150 that receive the needles 1156. Invarious instances, the needles 1156 can be heated prior to theirinsertion into the tissue thickness compensator 1150. In variousinstances, the needles 1156 can be heated after their insertion into thetissue thickness compensator 1150. In various instances, the needles1156 can be gradually heated as the needles 1156 are inserted into thetissue thickness compensator 1150.

In certain instances, the needles 1156 may remain positioned within thetissue thickness compensator 1150 for a period of time sufficient topermit the melted material of the tissue thickness compensator 1150 toflow into a desired geometry. Such a time period can range from about 30seconds to about 8 hours, for example; other time periods arecontemplated by the present disclosure. Such a time period can besufficient to locally affect and/or melt the material of the tissuethickness compensator 1150 and have it flow into a new geometry. Asdescribed herein, such a new geometry can be prescribed by the toolingused to make the tissue thickness compensator 1150.

In certain instances, the tissue thickness compensator 1150 can beallowed to cool, or can be actively cooled, to a temperature below themelting temperature of the tissue thickness compensator 1150 beforeseparating the needles 1156 from the tissue thickness compensator 1150.In other instances, the tissue thickness compensator 1150 can be allowedto cool, or can be actively cooled, to a temperature below the meltingtemperature of the tissue thickness compensator 1150 after separatingthe needles 1156 from the tissue thickness compensator 1150.

Referring again to FIGS. 32-34, the needles 1156 can be arranged in rowsextending longitudinally along a length of the mold 1154 which maycorrespond to staple rows in a staple cartridge such as, for example,the staple cartridge assembly 20200 (FIG. 6). For example, asillustrated in FIG. 33, the needles 1156 can are arranged in six rowswhich can be configured to create six rows of the apertures 1152 thatcan be configured to receive six rows of the staples 20230 (FIG. 7). Incertain circumstances, as illustrated in FIG. 33, the rows of theneedles 1156 can be arranged in two groups which are spaced apart andconfigured to be received in two portions 1158 and 1160 of the tissuethickness compensator 1150 thereby creating two groups of the apertures1152 separated by an intermediate portion 1162. The intermediate portion1162 can be positioned, at least partially, over the cartridge knifeslot 22015 (FIG. 6), when the tissue thickness compensator 1150 isassembled with staple cartridge assembly 20200. In use, the firingmember 10052 (FIG. 10) can be advanced distally to push the staple legs20232 (FIG. 8) through the apertures 1152 within the portions 1158 and1160 and advance the cutting portion 10053 (FIG. 10) to transect theintermediate portion 1162 and separate the portions 1158 and 1160.

Referring again to FIGS. 32-34, the apertures 1152 can be configured toextend within the tissue thickness compensator 1150 and terminate at acertain depth within the tissue thickness compensator 1150. Theapertures 1152 may comprise uniform depths, as illustrated in FIG. 34.In other circumstances, the apertures 1152 may comprise different depths(not shown). For example, a first row of the apertures 1152 may comprisea first depth and a second row of the apertures 1152 may comprise asecond depth different from the first depth and yet a third row of theapertures 1152 may comprise a third depth different from the first depthand the second depth. The depths of the apertures 1152 can bedetermined, at least in part, by the heights of the correspondingneedles 1156. For example, a first row of the needles 1156 comprising afirst height and a second row of the needles 1156 comprising secondheight greater than first height may create a first row of the apertures1152 comprising a first depth and a second row of the apertures 1152comprising a second depth which is greater than the first depth.

Referring again to FIGS. 32-34, the needles 1156 can be configured todefine a trajectory for the apertures 1152 within the tissue thicknesscompensator 1150. In certain circumstances, the needles 1156 can extendalong an axis that is perpendicular and/or substantially perpendicularto a mold surface 1164 of the mold 1154, as illustrated in FIG. 33.Inserting the needles 1156 into the tissue thickness compensator 1150while maintaining a parallel relationship between the mold surface 1164and a surface 1166 of the tissue thickness compensator 1150 may resultin defining a perpendicular and/or substantially perpendiculartrajectory for the apertures 1152 relative to the surface 1166 of thetissue thickness compensator 1150, as illustrated in FIG. 34. In othercircumstances, the needles 1156 can extend from the mold surface 1164 atan oblique angle (not shown) and/or the insertion trajectory of theneedles 1156 into the tissue thickness compensator 1150 can be at anangle such that the needles 1156 may define a non-perpendiculartrajectory for the apertures 1152 relative to the surface 1166 of thetissue thickness compensator 1150. In certain circumstances, a group ofthe needles 1156 can be parallel and/or substantially parallel to eachother, as illustrated in FIG. 33, resulting in a group of the apertures1152 that may be parallel and/or substantially parallel to each other,as illustrated in FIG. 24. In other circumstances, although notillustrated, a group of non-parallel needles can extend from the moldsurface 1164 and may result in non-parallel apertures when inserted intothe tissue thickness compensator 1150. In some circumstances, theneedles 1156 can be configured to create apertures within the tissuethickness compensator 1150 that can comprise a partially curvedtrajectory and/or a partially linear trajectory. For example, theneedles 1156 can extend from the mold surface 1164 in a partially curvedtrajectory and can be inserted into the tissue thickness compensator1150 to create apertures within the tissue thickness compensator 1150with a corresponding partially curved trajectory.

Referring again to FIGS. 32-34, some or all of the needles 1156 cancomprise blunt distal ends 1168, as illustrated in FIG. 33. In othercircumstances, some or all of the needles 1156 can comprise sharp distalends (not shown). Some or all of the needles 1156 can comprisecylindrical, or at least substantially cylindrical, shapes, for example,as illustrated in FIG. 33. Other shapes are also contemplated by thepresent disclosure.

In various instances, one or more of the needles 1156 extending from themold surface 1164 may not be insertable through the full thickness ofthe tissue thickness compensator 1150. In certain instances, one or moreof the needles 1156 extending from the mold surface 1164 can beinsertable through the full thickness of the tissue thicknesscompensator 1150 to create openings an/or holes that extend through thefull thickness of the tissue thickness compensator 1150. In certaininstances, one or more of the needles 1156 extending from the moldsurface 1164 can be inserted through a first side of the tissuethickness compensator 1150 and exited through a second side of thetissue thickness compensator 1150 which may be opposite the first side,for example. In certain instances, one or more of the needles 1156 maycomprise a length greater than the full thickness of the tissuethickness compensator 1150 to facilitate the insertion of the one ormore needles 1156 through the full thickness of the tissue thicknesscompensator 1150.

Referring now to FIGS. 35-37, it may be desirable to resize a tissuethickness compensator. For example, one or more dimensions of a tissuethickness compensator may be adjusted to correspond to dimensions of astaple cartridge in order to provide a better fit to the staplecartridge when the tissue thickness compensator is assembled with thestaple cartridge. In certain circumstances, a tissue thicknesscompensator 1170 can be resized by changing its height from a firstheight H1, as illustrated in FIG. 35, to a second height H2, asillustrated in FIG. 36. The tissue thickness compensator 1170 may besimilar in many respects to other tissue thickness compensatorsdescribed herein such as, for example, the tissue thickness compensator22020 (FIG. 9), the tissue thickness compensator 1140 (FIG. 29), and/orthe tissue thickness compensator 1150 (FIG. 32). For example, like thecompensator 22020, the compensator 1170 can be utilized with the endeffector 22090 (FIG. 9).

In various instances, referring again to FIGS. 35-37, the tissuethickness compensator 1170 can be prepared using traditionallyophilization techniques and/or any other suitable techniques. Incertain instances, the tissue thickness compensator 1170 can be resized,as illustrated in FIG. 37, using a thermal pressing process and a mold1172, for example. The mold 1172 may comprise a receiver 1174 configuredto receive the tissue thickness compensator 1170 and an adjustmentmember 1176 which can be partially insertable into the receiver 1174.The tissue thickness compensator 1170 can be resized when the tissuethickness compensator 1170 is transitioned into a glassy state. In oneembodiment, the tissue thickness compensator 1170 can be heated in anoven (not shown) to a temperature greater than or equal to a glasstransition temperature of the material composition of the tissuethickness compensator 1170 but less than the melting temperature of thesame. In another embodiment, the receiver 1174 and/or the adjustmentmember 1176 may comprise a heating element for transitioning the tissuethickness compensator 1170 to the glassy state. The adjustment member1176 can then be inserted into the receiver 1174 a distance H3, forexample, as illustrated in FIG. 37, thereby compressing the tissuethickness compensator 1170 and reducing its height from the first heightH1 to the second height H2. In some instances, the adjustment member1176 can be inserted into the receiver 1174 before the tissue thicknesscompensator 1170 enters into the glassy state or just as the tissuethickness compensator 1170 enters into the glassy state. The adjustmentmember 1176 can be held against the tissue thickness compensator 1170 tocompress the tissue thickness compensator 1170 for a time periodsufficient to permit the tissue thickness compensator 1170 to retain, orat least substantially retain, the second height H2, as illustrated inFIG. 36. The tissue thickness compensator 1170 can then be allowed tocool to a temperature below the glass transition temperature while undercompression from the adjustment member 1176. After transitioning thetissue thickness compensator 1170 out of the glassy state, theadjustment member 1176 can be retracted. In some instances, theadjustment member 1176 can be retracted before the tissue thicknesscompensator 1170 exits the glassy state. In certain circumstances, theabove described resizing process can be utilized to change anotherdimension of the tissue thickness compensator 1170 such as a length or awidth of the tissue thickness compensator 1170, for example. In somecircumstances, these dimensions can be modified simultaneously ormodified sequentially.

In certain examples, the compression from the adjustment member 1176 canbe maintained for a period of time from about 30 seconds to about 8hours, for example, during the time in the glassy state and/or for aperiod of time from about 30 seconds to about 8 hours, for example,after exiting the glassy state. In at least one example, the compressionfrom the adjustment member 1176 can be maintained for approximately 10minutes during the time in the glassy state and for approximately 10minutes after exiting the glassy state. Other time periods formaintaining the compression imposed by the adjustment member 1176against the tissue thickness compensator 1170 are contemplated by thepresent disclosure.

In certain circumstances, the adjustment member 1176 can be used toapply pressure onto the tissue thickness compensator 1170 before thetissue thickness compensator 1170 is transitioned to the glassy state.In certain circumstances, the adjustment member 1176 may apply pressureto the tissue thickness compensator 1170 while the tissue thicknesscompensator 1170 is heated to reach the glassy state, while the tissuethickness compensator 1170 is in the glassy state, and/or while thetissue thickness compensator 1170 is transitioned or cooled to atemperature below the glassy state. In certain circumstances, thepressure applied to the tissue thickness compensator 1170 can begradually increased toward a threshold as the temperature of the tissuethickness compensator 1170 is gradually transitioned toward the glassystate, for example. In certain circumstances, the pressure applied tothe tissue thickness compensator 1170 can be removed, gradually removed,or at least partially reduced as the tissue thickness compensator 1170exits the glassy state, before the tissue thickness compensator 1170exits the glassy state, and/or after the tissue thickness compensator1170 exits the glassy state.

The reader will appreciate that the different molds utilized in themodification processes described above such as, for example, the molds1144, 1154, and/or 1172 are illustrative examples. Other mold designsand configurations can also be employed to manipulate tissue thicknesscompensators in a variety of ways. Furthermore, the forces involved inmanipulating a tissue thickness compensator need not only be compressiveforces. For example, tensile forces can also be utilized to modify,reshape, and/or resize a tissue thickness compensator in similar mannersto those described above. For example, the tissue thickness compensator1170 can be stretched using tensile forces to reduce its height from thefirst height H1 (FIG. 35) to the second height H2 (FIG. 36), forexample, using a modification process that is similar in many respectsto the modification processes described above. In certain circumstances,combinations of tensile and compressive forces can be used to manipulatea tissue thickness compensator during a modification process.

Referring again to FIGS. 35-37, it may be desirable to modify theporosity of a tissue thickness compensator for use in a surgicalprocedure. A tissue thickness compensator may comprise a porous, opencell foam and/or a porous, closed cell foam, for example. Traditionallyophilization techniques may provide some control over a tissuethickness compensator's porosity but such control may not be easilyreproducible and may need additional fine adjustments that may not beobtainable by traditional lyophilization techniques. As illustrated inFIGS. 35-37, the height of the tissue thickness compensator 1170 can bechanged from the first height H1 (FIG. 35) to the second height H2 (FIG.36), for example, using the modification process described above. Inaddition, porosity of the tissue thickness compensator 1170 can also bemodified using the same and/or a similar modification process. Forexample, the tissue thickness compensator 1170 may comprise a firstporosity (FIG. 35) prior to the modification process and a secondporosity (FIG. 36) after completion of the modification process, asdescribed above. The change in porosity can be attributed, at least inpart, to the compressive forces and/or the energy applied to the tissuethickness compensator 1170 by the adjustment member 1176 during themodification process described above.

Further to the above, the tissue thickness compensator 1170 may comprisea plurality of pores 1180. Some or all of the pores 1180 may be alteredin position, size, and/or shape, for example, as a result of themodification process described above. For example, one or more of thepores 1180 may comprise a spherical, or substantially spherical, shapeprior to the modification process which may be altered to an oval, orsubstantially oval, shape as a result of the modification process. In atleast one example, one or more of the pores 1180 may comprise a firstsize prior to the modification process and a second size different fromthe first size as a result of the modification process. In certaincircumstances, as described below in greater detail, the porositychanges can be localized to one or more regions or zones of the tissuethickness compensator 1170.

Furthermore, in certain circumstances, the change in porosity of thetissue thickness compensator 1170 may be accompanied by a change indensity of the tissue thickness compensator 1170. In other words, as theadjustment member 1176 is advanced against the tissue thicknesscompensator 1170, compressive forces may reduce space occupied by thetissue thickness compensator 1170 thereby causing material and/or poreredistribution which may yield an increase in the density of the tissuethickness compensator 1170 and/or a reduction in its porosity. Incertain circumstances, as described below in greater detail, the densitychanges can be localized to one or more regions or zones of the tissuethickness compensator 1170.

Further to the above, the change in porosity and/or density of thetissue thickness compensator 1170 may yield a change in the spring rateof the tissue thickness compensator 1170. A tissue thicknesscompensator's spring rate can influence its ability to compensate fortissue thickness when the tissue thickness compensator is deployedagainst tissue captured by staples such as, for example, the staples20230 (FIG. 8), as described above in greater detail. Furthermore, atissue thickness compensator's spring rate can also influence itsability to apply pressure against tissue captured with the tissuethickness compensator by a staple. In other words, a change in a tissuethickness compensator's spring rate may change the pressure exerted bythe tissue thickness compensator against tissue captured by a staple.Since different tissue types may respond more positively to certainpressures, fine control over a tissue thickness compensator's springrate can be advantageous.

As illustrated in FIGS. 35-37, the tissue thickness compensator 1170 maycomprise a first spring rate (FIG. 35) which may be altered or modifiedto a second spring rate (FIG. 36) different from the first spring rateusing the modification process described above. For example, asdescribed above, the adjustment member 1176 can be advanced against thetissue thickness compensator 1170 while the tissue thickness compensator1170 is in the glassy state. In response, the tissue thicknesscompensator 1170 may be compressed which may cause a change in thespring rate of the tissue thickness compensator 1170. The adjustmentmember 1176 can be retained in the advanced position for a period oftime sufficient to permit the tissue thickness compensator 1170 toretain, or at least substantially retain, the change in spring rate. Inaddition, the tissue thickness compensator 1170 can be allowed to coolbelow the glass transition temperature of its material composition whilemaintaining the pressure applied by the adjustment member 1176 againstthe tissue thickness compensator 1170.

In certain instances, the adjustment member 1176 can be maintained inthe advanced position against the tissue thickness compensator 1170 fora period of time from about 30 seconds to about 8 hours, for example,during the time in the glassy state and/or for a period of time fromabout 30 seconds to about 8 hours, for example, after exiting the glassystate. In at least one example, the adjustment member 1176 can bemaintained in the advanced position against the tissue thicknesscompensator 1170 for approximately 10 minutes during the time in theglassy state and for approximately 10 minutes after exiting the glassystate. Other time periods for maintaining the adjustment member 1176 inthe advanced position against the tissue thickness compensator 1170 arecontemplated by the present disclosure.

In certain circumstances, the adjustment member 1176 can be used toapply pressure onto the tissue thickness compensator 1170 to change thespring rate of the tissue thickness compensator 1170 before the tissuethickness compensator 1170 is transitioned to the glassy state. Incertain circumstances, the adjustment member 1176 may apply pressure tothe tissue thickness compensator 1170 while the tissue thicknesscompensator 1170 is heated to reach the glassy state, while the tissuethickness compensator 1170 is in the glassy state, and/or while thetissue thickness compensator 1170 is transitioned or cooled to atemperature below the glassy state. In certain circumstances, thepressure applied to the tissue thickness compensator 1170 can begradually increased toward a threshold as the temperature of the tissuethickness compensator 1170 is gradually increased to transition thetissue thickness compensator 1170 toward the glassy state, for example.In certain circumstances, the pressure applied to the tissue thicknesscompensator 1170 can be removed, gradually removed, or at leastpartially reduced as the tissue thickness compensator 1170 exits theglassy state, before the tissue thickness compensator 1170 exits theglassy state, and/or after the tissue thickness compensator 1170 exitsthe glassy state.

Referring again to FIGS. 35-40, the tissue thickness compensator 1170may be manufactured with a native spring rate using traditionallyophilization techniques and/or any other suitable techniques. Asdescribed above, the spring rate of the tissue thickness compensator1170 can influence its ability to apply pressure against tissue capturedwith the tissue thickness compensator 1170 by a staple. The modificationprocess described above may be utilized to adjust the native spring rateof the tissue thickness compensator 1170 to adjust its ability to applypressure against tissue captured with the tissue thickness compensator1170 by the staple. In certain circumstances, the native spring rate ofthe tissue thickness compensator 1170 can be increased from a firstspring rate at point A (FIG. 40) to a second spring rate including andup to a maximum spring rate at point B (FIG. 40). In certaincircumstances, such increase of the spring rate of the tissue thicknesscompensator 1170 can be achieved by applying compression forces to thetissue thickness compensator 1170 using the adjustment member 1176 whilethe tissue thickness compensator 1170 is in the glassy state, as explainin the modification process described above. As illustrated in FIG. 40,the point B represents a maximum elastic yield of the tissue thicknesscompensator 1170. As such, any additional compression applied by theadjustment member 1176 to the tissue thickness compensator 1170 beyond athreshold compression at the point B may produce a decrease in thespring rate of the modified tissue thickness compensator 1170. Forexample, as illustrated in FIG. 40, the spring rate at the point C islower than the spring rate at the point B even though the compressionforce applied by the adjustment member 1176 to the tissue thicknesscompensator 1170 at point C is greater than the compression forceapplied at the point B.

As discussed above, one or more processes can be used to affect thespring rate, and/or any other property, of a material used inconjunction with a fastener cartridge and/or a surgical fasteninginstrument, for example. The spring rate, and/or any other property, ofthe material may change throughout the modification process orprocesses. Such a change may be gradual in some circumstances, while inother circumstances, the change may be sudden. In various instances, oneor more of the steps of the modification process may cause an increasein the spring rate of the material while one or more steps may cause adecrease in the spring rate of the material. Ultimately, the net changein the spring rate can be measured as a comparison between an originalspring rate before the modification process begins and a subsequentspring rate after the modification process has been completed. Invarious instances, a material may comprise an altered spring rate afterthe material has been heated and then cooled.

In certain circumstances, it may be desirable to apply one or more ofthe above described modification processes to a tissue thicknesscompensator. For example, a first modification process can be utilizedto modify porosity of the tissue thickness compensator, as describedabove with respect to the tissue thickness compensator 1170. A secondmodification process, following the first modification process, can beutilized to alter a surface of the tissue thickness compensator, asdescribed above with respect to the tissue thickness compensator 1140.Furthermore, a third modification process can be utilized to modify thetissue thickness compensator to include a longitudinal slot similar tothe longitudinal slot 1122 of the tissue thickness compensator 1120. Inyet a fourth modification process, the tissue thickness compensator canbe modified to include apertures similar to the apertures 1152 of thetissue thickness compensator 1150. The reader will appreciate that someof above mentioned modifications can be combined or grouped in a singlemodification process. For example, a mold can be designed to include theneedles 1156 of the mold 1154 and the central beam 1128 of the mold1126. Other modification arrangements are contemplated by the presentdisclosure.

Referring now to FIGS. 38 and 39, a tissue thickness compensator suchas, for example, tissue thickness compensator 1190 can be altered ormodified using one or more of the modification processes described aboveto include portions with different spring rates, porosities, and/ordensities. In certain circumstances, the tissue thickness compensator1190 can be modified using one or more of the modification processesdescribed above to include a gradient pore morphology (i.e. small poresgradually increasing in size to large pores across the thickness of thetissue thickness compensator 1190 in one direction). Such morphologycould be more optimal for tissue in-growth or hemostatic behavior.Further, the gradient could also be compositional with a varyingbio-absorption profile. A short term absorption profile may be preferredto address hemostasis while a long term absorption profile may addressbetter tissue healing without leakages.

Referring again to FIGS. 38 and 39, the tissue thickness compensator1190 may include one or more zone geometries that are different from theremainder of the tissue thickness compensator 1196. For example, asillustrated in FIG. 38, the tissue thickness compensator 1190 mayinclude one or more protruding portions such as, for example, protrudingportion 1196. In addition, the tissue thickness compensator 1190 maycomprise a uniform, or at least a substantially uniform, first springrate, first porosity, and/or first density through the tissue thicknesscompensator 1190 including the one or more zone geometries, asillustrated in FIG. 38. In certain circumstances, the tissue thicknesscompensator 1190 can be altered or modified using one or more of themodification processes described above to alter or modify the one ormore zone geometries and/or to induce localized changes in the firstspring rate, the first porosity, and/or the first density, for example.The modified tissue thickness compensator 1190 may comprise one or moremodified zones with different spring rates, porosities, and/or densitiesfrom other modified zones and/or the first spring rate, the firstporosity, and/or the first density, respectively, of the remainder ofthe tissue thickness compensator 1190. In certain circumstances, theresulting one or more modified zones may correspond to the one or morezone geometries. For example, as illustrated in FIG. 39, the tissuethickness compensator 1190 may be altered or modified to level, or atleast substantially level, the protruding portion 1196 and to form aflat, or at least a substantially flat, surface 1198, for example. Themodified tissue thickness compensator 1190 may include a first portion1192 comprising the first spring rate, the first porosity, and/or thefirst density and a second portion 1194 comprising a second spring rate,a second porosity, and/or a second density, which can be different fromthe first spring rate, the first porosity, and/or the first density,respectively. The second portion 1194 may correspond to the protrudingportion 1196 and can result from the leveling, or at least substantiallyleveling, of the protruding portion 1196 to form the flat, or at leastsubstantially flat, surface 1198, for example. In certain respects, thegeometry of the protruding portion 1196 prior to the modification of thetissue thickness compensator 1190 mirrors, matches, or resembles thegeometry of the second portion 1194 after the tissue thicknesscompensator 1190 has been modified.

Referring again to FIGS. 37-39, the tissue thickness compensator 1190can be altered or modified using the mold 1172, in a similar manner tothe tissue thickness compensator 1170. For example, the tissue thicknesscompensator 1190 can be heated in the receiver 1174 to a temperaturegreater than or equal to a glass transition temperature of the materialcomposition of the tissue thickness compensator 1190 but less than themelting temperature of the same. In certain circumstances, theadjustment member 1176 can be advanced against the protruding portion1196, while the tissue thickness compensator 1190 is in the glassystate, thereby compressing the protruding portion 1196 and rearrangingits geometry to form the second portion 1194, as illustrated in FIG. 39.Further to the above, the adjustment member 1176 can be configured tomaintain compression against the protruding portion 1196 for a timeperiod sufficient to permit the tissue thickness compensator 1190 toretain, or at least substantially retain, the modification imposed bythe adjustment member 1176. The tissue thickness compensator 1190 can beallowed to cool or can be actively cooled to a temperature below itsglass transition temperature while under compression from the adjustmentmember 1176. After transitioning the tissue thickness compensator 1190out of the glassy state, the adjustment member 1190 can be retracted.The tissue thickness compensator 1190 may retain, or at leastsubstantially retain, the second portion 1194, as illustrated in FIG.39. In certain circumstances, the adjustment member 1176 may applypressure onto the protruding portion 1196 while the tissue thicknesscompensator 1190 is heated to reach the glassy state, while the tissuethickness compensator 1190 is in the glassy state, and/or while thetissue thickness compensator 1190 is transitioned or cooled to atemperature below the glassy state. In certain circumstances, thepressure applied to the protruding portion 1196 of the tissue thicknesscompensator 1190 can be gradually increased toward a threshold as thetemperature of the tissue thickness compensator 1190 is graduallyincreased to transition the tissue thickness compensator 1190 toward theglassy state, for example. In certain circumstances, the pressureapplied to the protruding portion 1196 of the tissue thicknesscompensator 1190 can be removed, gradually removed, or at leastpartially reduced as the tissue thickness compensator 1190 exits theglassy state, before the tissue thickness compensator 1190 exits theglassy state, and/or after the tissue thickness compensator 1190 exitsthe glassy state.

Referring now to FIGS. 41-43, a tissue thickness compensator such as,for example, tissue thickness compensator 1200 can be prepared usingtraditional lyophilization techniques and/or any other suitabletechniques. In addition, the tissue thickness compensator 1200 can bemodified or altered for use in a surgical procedure, for example. Thetissue thickness compensator 1200 can be similar in many respects toother tissue thickness compensators such as, for example, the tissuethickness compensator 22020 (FIG. 9) and/or the tissue thicknesscompensator 1120 (FIG. 26). For example, like the tissue thicknesscompensator 22020, the tissue thickness compensator 1200 can be utilizedwith the end effector 22090. Furthermore, as illustrated in FIGS. 41-43,the tissue thickness compensator 1200 can be modified to include alongitudinal slot 1202 which, like the knife slot 22025, may define atissue thickness compensator knife path for the cutting portion 10053between a first stapling portion 1204 a and a second stapling portion1204 b. Furthermore, the first stapling portion 1204 a and the secondstapling portion 1204 b can be similar in many respects to the firststapling portion 22021 a (FIG. 9) and the second stapling portion 22021b (FIG. 9) of the tissue thickness compensator 22020. In addition, theslot 1202 can be configured to releasably connect the first staplingportion 1204 a and the second stapling portion 1204 b such that, in usewith the end effector 22090, the cutting portion 10053 can be advanceddistally through the slot 1202 to transect the slot 1202 and separatethe first stapling portion 1204 a and the second stapling portion 1204b.

Referring again to FIGS. 41-43, the tissue thickness compensator 1200can be modified prior to assembly with an end effector such as, forexample, the end effector 22090 (FIG. 9). Alternatively, the tissuethickness compensator 1200 can be modified after it has been assembledwith an end effector. As described above, the tissue thicknesscompensator 1200 can be prepared using traditional lyophilizationtechniques and/or any other suitable techniques. A space creator 1206can be utilized to modify the tissue thickness compensator 1200 in athermal pressing process, as illustrated in FIGS. 41-43. For example,the space creator 1206 can be heated to a temperature greater than orequal to a melting temperature of the material composition of the tissuethickness compensator 1200. The space creator 1206 can then be alignedwith and inserted into the tissue thickness compensator 1200 to form thelongitudinal slot 1202. The space creator 1206 may melt through thetissue thickness compensator 1200 to create space for the longitudinalslot 1202. The space creator 1206 can be retracted upon reaching adesired depth within the tissue thickness compensator 1200. In certaincircumstances, the thermal pressing process can be repeated byreinserting the heated space creator 1206 through the tissue thicknesscompensator 1200 to widen the space created for the longitudinal slot1202.

Referring again to FIGS. 41-43, the space creator 1206 may comprise ahot wire. For example, the space creator 1206 may comprise a thin, tautmetal wire, which can be made of nichrome or stainless steel, forexample, or a thicker wire preformed into a desired shape. The hot wirecan be heated via electrical resistance to a desired temperature. As thehot wire of the space creator 1206 is passed through the material of thetissue thickness compensator 1200, the heat from the hot wire mayvaporize the material just in advance of contact. In certaincircumstances, the hot wire may comprise a cylindrical, or substantiallycylindrical, shape, as illustrated in FIG. 42. The depth of thelongitudinal slot 1202 can depend, in part, on the insertion depth ofthe space creator 1206 through the tissue thickness compensator 1200 andthe width of the longitudinal slot 1202 can depend, in part, on thediameter of the hot wire of the space creator 1206.

In certain instances, the space creator 1206 can be partially insertedthrough the full thickness of the tissue thickness compensator. Incertain instances, the space creator 1206 can be completely insertedthrough the full thickness of the tissue thickness compensator 1200 tocreate openings, holes, and/or slots extending through the fullthickness of the tissue thickness compensator 1200. In certaininstances, the space creator 1206 may be inserted through a first sideof the tissue thickness compensator 1200 and exited through a secondside of the tissue thickness compensator 1200 which may be opposite thefirst side, for example.

Many processes are disclosed herein which utilize thermal energy tomodify a tissue thickness compensator. Such processes can be referred toas felting processes. In certain instances, a felting process may alsoutilize the application of compressive and/or tensile forces to a tissuethickness compensator. In other instances, a felting process may notutilize the application of compressive and/or tensile forces to a tissuethickness compensator. In either event, the felting processes disclosedherein can also be utilized to modify and suitable implantable layerand/or buttress material, for example.

In various circumstances, the tissue thickness compensator assembly maycomprise a polymeric composition. The polymeric composition may compriseone or more synthetic polymer and/or one or more non-synthetic polymer.The synthetic polymer may comprise a synthetic absorbable polymer and/ora synthetic non-absorbable polymer. In various circumstances, thepolymeric composition may comprise a biocompatible foam, for example.The biocompatible foam may comprise a porous, open cell foam and/or aporous, closed cell foam, for example. The biocompatible foam can have auniform pore morphology or may have a gradient pore morphology (i.e.small pores gradually increasing in size to large pores across thethickness of the foam in one direction). In various circumstances, thepolymeric composition may comprise one or more of a porous scaffold, aporous matrix, a gel matrix, a hydrogel matrix, a solution matrix, afilamentous matrix, a tubular matrix, a composite matrix, a membranousmatrix, a biostable polymer, and a biodegradable polymer, andcombinations thereof. For example, the tissue thickness compensatorassembly may comprise a foam reinforced by a filamentous matrix or maycomprise a foam having an additional hydrogel layer that expands in thepresence of bodily fluids to further provide the compression on thetissue. In various circumstances, a tissue thickness compensatorassembly could also be comprised of a coating on a material and/or asecond or third layer that expands in the presence of bodily fluids tofurther provide the compression on the tissue. Such a layer could be ahydrogel that could be a synthetic and/or naturally derived material andcould be either biodurable and/or biodegradable, for example. In certaincircumstances, a tissue thickness compensator assembly could bereinforced with fibrous non-woven materials or fibrous mesh typeelements, for example, that can provide additional flexibility,stiffness, and/or strength. In various circumstances, a tissue thicknesscompensator assembly that has a porous morphology which exhibits agradient structure such as, for example, small pores on one surface andlarger pores on the other surface. Such morphology could be more optimalfor tissue in-growth or hemostatic behavior. Further, the gradient couldbe also compositional with a varying bio-absorption profile. A shortterm absorption profile may be preferred to address hemostasis while along term absorption profile may address better tissue healing withoutleakages.

Examples of non-synthetic polymers include, but are not limited to,lyophilized polysaccharide, glycoprotein, elastin, proteoglycan,gelatin, collagen, and oxidized regenerated cellulose (ORC). Examples ofsynthetic absorbable polymers include, but are not limited to,poly(lactic acid) (PLA), poly(L-lactic acid) (PLLA), polycaprolactone(PCL), polyglycolic acid (PGA), poly(trimethylene carbonate) (TMC),polyethylene terephthalate (PET), polyhydroxyalkanoate (PHA), acopolymer of glycolide and ε-caprolactone (PGCL), a copolymer ofglycolide and -trimethylene carbonate, poly(glycerol sebacate) (PGS),polydioxanone, poly(orthoesters), polyanhydrides, polysaccharides,poly(ester-amides), tyrosine-based polyarylates, tyrosine-basedpolyiminocarbonates, tyrosine-based polycarbonates,poly(D,L-lactide-urethane), poly(B-hydroxybutyrate),poly(E-caprolactone), polyethyleneglycol (PEG),poly[bis(carboxylatophenoxy) phosphazene], poly(amino acids),pseudo-poly(amino acids), absorbable polyurethanes, and combinationsthereof. In various circumstances, the polymeric composition maycomprise from approximately 50% to approximately 90% by weight of thepolymeric composition of PLLA and approximately 50% to approximately 10%by weight of the polymeric composition of PCL, for example. In at leastone embodiment, the polymeric composition may comprise approximately 70%by weight of PLLA and approximately 30% by weight of PCL, for example.In various circumstances, the polymeric composition may comprise fromapproximately 55% to approximately 85% by weight of the polymericcomposition of PGA and 15% to 45% by weight of the polymeric compositionof PCL, for example. In at least one embodiment, the polymericcomposition may comprise approximately 65% by weight of PGA andapproximately 35% by weight of PCL, for example. In variouscircumstances, the polymeric composition may comprise from approximately90% to approximately 95% by weight of the polymeric composition of PGAand approximately 5% to approximately 10% by weight of the polymericcomposition of PLA, for example.

In various circumstances, the synthetic absorbable polymer may comprisea bioabsorbable, biocompatible elastomeric copolymer. Suitablebioabsorbable, biocompatible elastomeric copolymers include but are notlimited to copolymers of epsilon-caprolactone and glycolide (preferablyhaving a mole ratio of epsilon-caprolactone to glycolide of from about30:70 to about 70:30, preferably 35:65 to about 65:35, and morepreferably 45:55 to 35:65); elastomeric copolymers ofepsilon-caprolactone and lactide, including L-lactide, D-lactide blendsthereof or lactic acid copolymers (preferably having a mole ratio ofepsilon-caprolactone to lactide of from about 35:65 to about 65:35 andmore preferably 45:55 to 30:70) elastomeric copolymers of p-dioxanone(1,4-dioxan-2-one) and lactide including L-lactide, D-lactide and lacticacid (preferably having a mole ratio of p-dioxanone to lactide of fromabout 40:60 to about 60:40); elastomeric copolymers ofepsilon-caprolactone and p-dioxanone (preferably having a mole ratio ofepsilon-caprolactone to p-dioxanone of from about 30:70 to about 70:30);elastomeric copolymers of p-dioxanone and trimethylene carbonate(preferably having a mole ratio of p-dioxanone to trimethylene carbonateof from about 30:70 to about 70:30); elastomeric copolymers oftrimethylene carbonate and glycolide (preferably having a mole ratio oftrimethylene carbonate to glycolide of from about 30:70 to about 70:30);elastomeric copolymer of trimethylene carbonate and lactide includingL-lactide, D-lactide, blends thereof or lactic acid copolymers(preferably having a mole ratio of trimethylene carbonate to lactide offrom about 30:70 to about 70:30) and blends thereof. In one embodiment,the elastomeric copolymer is a copolymer of glycolide andepsilon-caprolactone. In another embodiment, the elastomeric copolymeris a copolymer of lactide and epsilon-caprolactone.

The disclosures of U.S. Pat. No. 5,468,253, entitled ELASTOMERIC MEDICALDEVICE, which issued on Nov. 21, 1995, and U.S. Pat. No. 6,325,810,entitled FOAM BUTTRESS FOR STAPLING APPARATUS, which issued on Dec. 4,2001, are hereby incorporated by reference in their respectiveentireties.

In various circumstances, the synthetic absorbable polymer may compriseone or more of 90/10 poly(glycolide-L-lactide) copolymer, commerciallyavailable from Ethicon, Inc. under the trade designation VICRYL(polyglactic 910), polyglycolide, commercially available from AmericanCyanamid Co. under the trade designation DEXON, polydioxanone,commercially available from Ethicon, Inc. under the trade designationPDS, poly(glycolide-trimethylene carbonate) random block copolymer,commercially available from American Cyanamid Co. under the tradedesignation MAXON, 75/25poly(glycolide-E-caprolactone-poliglecaprolactone 25) copolymer,commercially available from Ethicon under the trade designationMONOCRYL, for example.

Examples of synthetic non-absorbable polymers include, but are notlimited to, foamed polyurethane, polypropylene (PP), polyethylene (PE),polycarbonate, polyamides, such as nylon, polyvinylchloride (PVC),polymethylmetacrylate (PMMA), polystyrene (PS), polyester,polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE),polytrifluorochloroethylene (PTFCE), polyvinylfluoride (PVF),fluorinated ethylene propylene (FEP), polyacetal, polysulfone, andcombinations thereof. The synthetic non-absorbable polymers may include,but are not limited to, foamed elastomers and porous elastomers, suchas, for example, silicone, polyisoprene, and rubber. In variouscircumstances, the synthetic polymers may comprise expandedpolytetrafluoroethylene (ePTFE), commercially available from W. L. Gore& Associates, Inc. under the trade designation GORE-TEX Soft TissuePatch and co-polyetherester urethane foam commercially available fromPolyganics under the trade designation NASOPORE.

The polymeric composition of a tissue thickness compensator assembly maybe characterized by percent porosity, pore size, and/or hardness, forexample. In various circumstances, the polymeric composition may have apercent porosity from approximately 30% by volume to approximately 99%by volume, for example. In certain circumstances, the polymericcomposition may have a percent porosity from approximately 60% by volumeto approximately 98% by volume, for example. In various circumstances,the polymeric composition may have a percent porosity from approximately85% by volume to approximately 97% by volume, for example. In at leastone embodiment, the polymeric composition may comprise approximately 70%by weight of PLLA and approximately 30% by weight of PCL, for example,and can comprise approximately 90% porosity by volume, for example. Inat least one such embodiment, as a result, the polymeric compositionwould comprise approximately 10% copolymer by volume. In at least oneembodiment, the polymeric composition may comprise approximately 65% byweight of PGA and approximately 35% by weight of PCL, for example, andcan have a percent porosity from approximately 93% by volume toapproximately 95% by volume, for example. In various circumstances, thepolymeric composition may comprise a greater than 85% porosity byvolume. The polymeric composition may have a pore size fromapproximately 5 micrometers to approximately 2000 micrometers, forexample. In various circumstances, the polymeric composition may have apore size between approximately 10 micrometers to approximately 100micrometers, for example. In at least one such embodiment, the polymericcomposition can comprise a copolymer of PGA and PCL, for example. Incertain circumstances, the polymeric composition may have a pore sizebetween approximately 100 micrometers to approximately 1000 micrometers,for example. In at least one such embodiment, the polymeric compositioncan comprise a copolymer of PLLA and PCL, for example. According tocertain aspects, the hardness of a polymeric composition may beexpressed in terms of the Shore Hardness, which can defined as theresistance to permanent indentation of a material as determined with adurometer, such as a Shore Durometer. In order to assess the durometervalue for a given material, a pressure is applied to the material with adurometer indenter foot in accordance with ASTM procedure D2240-00,entitled, “Standard Test Method for Rubber Property-Durometer Hardness”,the entirety of which is incorporated herein by reference. The durometerindenter foot may be applied to the material for a sufficient period oftime, such as 15 seconds, for example, wherein a reading is then takenfrom the appropriate scale. Depending on the type of scale being used, areading of 0 can be obtained when the indenter foot completelypenetrates the material, and a reading of 100 can be obtained when nopenetration into the material occurs. This reading is dimensionless. Invarious circumstances, the durometer may be determined in accordancewith any suitable scale, such as Type A and/or Type OO scales, forexample, in accordance with ASTM D2240-00. In various circumstances, thepolymeric composition of a tissue thickness compensator assembly mayhave a Shore A hardness value from approximately 4 A to approximately 16A, for example, which is approximately 45 OO to approximately 65 OO onthe Shore OO range. In at least one such embodiment, the polymericcomposition can comprise a PLLA/PCL copolymer or a PGA/PCL copolymer,for example. In various circumstances, the polymeric composition of atissue thickness compensator assembly may have a Shore A Hardness valueof less than 15 A. In various circumstances, the polymeric compositionof a tissue thickness compensator assembly may have a Shore A Hardnessvalue of less than 10 A. In various circumstances, the polymericcomposition of a tissue thickness compensator assembly may have a ShoreA Hardness value of less than 5 A. In certain circumstances, thepolymeric material may have a Shore OO composition value fromapproximately 35 OO to approximately 75 OO, for example.

In various circumstances, the polymeric composition may have at leasttwo of the above-identified properties. In various circumstances, thepolymeric composition may have at least three of the above-identifiedproperties. The polymeric composition may have a porosity from 85% to97% by volume, a pore size from 5 micrometers to 2000 micrometers, and aShore A hardness value from 4 A to 16 A and Shore OO hardness value from45 OO to 65 OO, for example. In at least one embodiment, the polymericcomposition may comprise 70% by weight of the polymeric composition ofPLLA and 30% by weight of the polymeric composition of PCL having aporosity of 90% by volume, a pore size from 100 micrometers to 1000micrometers, and a Shore A hardness value from 4 A to 16 A and Shore OOhardness value from 45 OO to 65 OO, for example. In at least oneembodiment, the polymeric composition may comprise 65% by weight of thepolymeric composition of PGA and 35% by weight of the polymericcomposition of PCL having a porosity from 93% to 95% by volume, a poresize from 10 micrometers to 100 micrometers, and a Shore A hardnessvalue from 4 A to 16 A and Shore OO hardness value from 45 OO to 65 OO,for example.

In various circumstances, the polymeric composition may comprise apharmaceutically active agent. The polymeric composition may release atherapeutically effective amount of the pharmaceutically active agent.In various circumstances, the pharmaceutically active agent may bereleased as the polymeric composition is desorbed/absorbed. In variouscircumstances, the pharmaceutically active agent may be released intofluid, such as, for example, blood, passing over or through thepolymeric composition. Examples of pharmaceutically active agents mayinclude, but are not limited to, hemostatic agents and drugs, such as,for example, fibrin, thrombin, and oxidized regenerated cellulose (ORC);anti-inflammatory drugs, such as, for example, diclofenac, aspirin,naproxen, sulindac, and hydrocortisone; antibiotic and antimicrobialdrug or agents, such as, for example, triclosan, ionic silver,ampicillin, gentamicin, polymyxin B, chloramphenicol; and anticanceragents, such as, for example, cisplatin, mitomycin, adriamycin.

Various methods are disclosed herein for altering a tissue thicknesscompensator. Such methods could be used to alter any suitable layer foruse with a fastener cartridge and/or a surgical fastening instrument,for example. Such a layer can comprise a less than one hundred percentdense composition which can be created utilizing any suitable process.For instance, such processes can include, for example, extruding,injection molding, weaving, lyophilization, gas-foaming, and/ormelt-blowing processes. Some processes may produce a foam while otherprocesses may not produce a foam; however, in any event, all suchembodiments are contemplated for use with all of the embodimentsdisclosed herein.

In various embodiments, referring to FIGS. 44-46, an end effector of asurgical fastening instrument, such as end effector 100, for example,can be configured to capture, fasten, and/or incise tissue. The endeffector 100 can include a fastener cartridge 110 and, in addition, afiring member 140 which can be advanced through the fastener cartridge110 to deploy staples removably stored within the staple cartridge 110into tissue captured within the end effector 100. In various instances,the firing member 140 can be advanced from a proximal position (FIG. 44)toward a distal end of the end effector 100 to simultaneously deploy thestaples and transect the tissue. There are some circumstances, however,where it may not be desirable to advance the firing member 140 towardthe distal end of the end effector 100. For instance, the fastenercartridge 110 of the end effector 100 can be removable and/orreplaceable and, in the event that a fastener cartridge 110 is notpositioned within the end effector 100, it may not be desirable for thefiring member 140 to be advanced within the end effector 100. In theevent that the firing member 140 were to be advanced through the endeffector 100 without a fastener cartridge positioned within the endeffector 100, a knife edge 142 of the firing member 140 may incisetissue captured within the end effector 100 without simultaneouslyfastening the tissue. Similarly, in the event that the fastenercartridge positioned within the end effector 100 has been previouslyused, or expended, and at least some of the fasteners have been deployedfrom the fastener cartridge, it may not be desirable for the firingmember 140 to be advanced within the end effector 100. In the event thatthe firing member 140 were to be advanced through the end effector 100with a previously expended fastener cartridge positioned within the endeffector 100, the knife edge 142 of the firing member 140 may incisetissue captured within the end effector without simultaneously fasteningthe tissue. In various embodiments, the end effector 100 can include oneor more lockout systems which can prevent the firing member 140 frombeing advanced distally when a fastener cartridge is not present withinthe end effector 100 and/or when the fastener cartridge positionedwithin the end effector 100 has been at least partially expended.Various lockout systems are disclosed in U.S. Pat. No. 6,988,649,entitled SURGICAL STAPLING INSTRUMENT HAVING A SPENT CARTRIDGE LOCKOUT,and issued on Jan. 24, 2006. The entire disclosure of U.S. Pat. No.6,988,649, entitled SURGICAL STAPLING INSTRUMENT HAVING A SPENTCARTRIDGE LOCKOUT, is incorporated by reference herein.

Referring again to FIGS. 44-46, the fastener cartridge 110 can include acartridge body and a tissue thickness compensator 120 wherein, furtherto the above, the tissue thickness compensator 120 can be implantedagainst tissue captured by the end effector 100 by fasteners removablystored within the cartridge body. The tissue thickness compensator 120can be positioned above a top surface, or deck, of the cartridge bodywherein staples 180 removably stored within staple cavities defined inthe cartridge body can be ejected from the staple cavities by a firingmember, such as sled 130 and/or firing member 140, for example. Incertain embodiments, the fastener cartridge 110 can further includedrivers configured to support the staples 180 and transmit the movementof the sled 130 to the staples 180 in order to move the staples 180between an unfired position and a fired position. In various instances,the staples 180 can be at least partially embedded in the tissuethickness compensator 120 when the staples 180 are in their unfiredpositions and, in certain instances, the staples 180 can hold the tissuethickness compensator 120 in position over the cartridge deck when thestaples 180 are in their unfired position. In the event that the tissuethickness compensator 120 were to be moved relative to the cartridgebody and/or the staples 180 prior to deploying the staples 180 intotissue, in some instances, the tissue thickness compensator 120 may movethe staples 180 relative to or away from their preferred positions.Moreover, in the event that the tissue thickness compensator 120 were tobe removed from the cartridge 110 prior to the staples 180 beingdeployed, the cartridge 110 may no longer be suitable for its originallyintended use. In view of the foregoing, as discussed in greater detailbelow, the end effector 100 may include a lockout configured to preventthe firing member 140 and/or the sled 130 from being advanced distallyto deploy the staples 180 in the event that the tissue thicknesscompensator 120 is removed from, or becomes at least partially dislodgedfrom, the cartridge body prior to the staples 180 being deployed.

Referring again to FIGS. 44-46, the tissue thickness compensator 120 cancomprise, one, a body 121 configured to be captured by the staples 180and, two, a lockout pin 122 extending from the body 121. In variousinstances, the lockout pin 122 can include a first end 123 embedded inthe body 121 and a second end 124 positioned intermediate the firingmember 140 and the sled 130 when the tissue thickness compensator 120has not been removed from or substantially moved from a suitableposition over the cartridge body deck. In such a position, the secondend 124 of the lockout pin 122 can be positioned intermediate ashoulder, or shelf, 134 defined on the sled 130 and a protrusion 144extending distally from the firing bar 140. Stated another way, when thelockout pin 122 is positioned intermediate the sled 130 and the firingbar 140, the lockout pin 122 and the sled 130 can co-operate to supportthe firing bar 140 in an unlocked position above a lockout shoulder 112defined in the fastener cartridge 110 such that, when a distal firingforce is applied to the firing bar 140, the firing bar 140 can advancethe sled 130 distally to fire the staples 180. When the tissue thicknesscompensator 120 is removed from the cartridge 110 and/or sufficientlydislodged from a desirable position relative to the cartridge body,referring primarily to FIG. 45, the lockout pin 122 may no longer bepositioned intermediate the sled 130 and the firing member 140 and/ormay otherwise be unable to support the firing member 140 in its unlockedposition (FIG. 44). In such circumstances, the firing member 140 maybecome positioned in a locked position such that the distal advancementof the firing member 140 is prevented by the lockout shoulder 112. In atleast one such circumstance, the end effector 100 can further include abiasing member, such as a spring, for example, configured to bias thefiring member 140 into its locked condition. In certain circumstances,the biasing member can bias the firing member 140 into contact with thesled 130, for instance, without the lockout pin 122 positionedtherebetween which can comprise the locked position of the firing member140.

As a result of the above, the cartridge 110 may become inoperable if thetissue thickness compensator 120 is prematurely removed from thecartridge 110. In such circumstances, the lockout pin 122 may comprise afuse which deactivates the cartridge 110 in the event that the tissuethickness compensator 120 is removed before the firing member 140 isadvanced distally. In various circumstances, the lockout pin 122 maycomprise a key which maintains the cartridge 110 in an unlockedcondition when the key is positioned between the sled 130 and the firingmember 140 and permits the cartridge 110 to enter into a lockedcondition in the event that the tissue thickness compensator 120 isremoved from the cartridge 110 before the firing member 140 is advanceddistally, i.e., before the firing member 140 begins its firing stroke.When the firing member 140 is in its locked-out condition and cannot beadvanced distally, the knife edge 142 of the firing member 140 is unableto incise the tissue captured within the end effector 100. Moreover, insuch circumstances, the firing member 140 cannot advance the sled 130distally to fire the staples 180. Thus, the tissue thickness compensatorlockout can prevent the tissue captured within the end effector 100 frombeing incised and stapled when the tissue thickness compensator 120 isnot positioned on, or properly positioned on, the cartridge 110. In theevent that the firing member 140 is advanced distally before the tissuethickness compensator 120 is removed, or dislodged, the firing member140 can complete the firing stroke, or at least a portion of the firingstroke, of the end effector 100. In such instances, the sled 130 isadvanced distally so that one or more ramps 132 defined on the sled 130can lift the staples 180 and that a knife edge 142 of the firing member140 can incise the tissue thickness compensator 120 and/or the tissuecaptured within the end effector 100. In some circumstances, the firingmember 140 can contact the lockout pin 122 and displace it out of theway as the firing member 140 is advanced distally. In suchcircumstances, the lockout pin 122 can be flexible. In variousinstances, the lockout pin 122 can be comprised of a bioabsorbablematerial and/or a biocompatible material, for example. In certaincircumstances, the firing member 140 can incise the lockout pin 122 asthe firing member 140 is advanced distally. In any event, the purpose ofthe lockout pin 122 may become obsolete once the firing member 140 hasbeen at least partially advanced. Stated another way, the tissuethickness compensator lockout can serve as an initial check to verifythat a tissue thickness compensator is present within the end effectorand, once that initial check has been made, the firing stroke of the endeffector can proceed.

Referring again to FIGS. 47-50, an end effector 200 can comprise ananvil 260 and, in addition, a fastener cartridge 210 including acartridge body 214 and a tissue thickness compensator 220 wherein,further to the above, the tissue thickness compensator 220 can beimplanted against tissue captured by the end effector 200 by fastenersremovably stored within the cartridge body 214. The tissue thicknesscompensator 220 can be positioned above a top surface, or deck, 211 ofthe cartridge body 214 wherein staples removably stored within staplecavities defined in the cartridge body 214 can be ejected from thestaple cavities by a firing member, such as a sled 230 and/or a firingmember 240, for example. In certain embodiments, the fastener cartridge210 can further include drivers configured to support the staples andtransmit the movement of the sled 230 to the staples in order to movethe staples between an unfired position and a fired position. In variousinstances, the staples can be at least partially embedded in the tissuethickness compensator 220 when the staples are in their unfiredpositions and, in certain instances, the staples can hold the tissuethickness compensator 220 in position when the staples are in theirunfired position. In the event that the tissue thickness compensator 220were to be moved relative to the cartridge body 214 and/or the staplesprior to deploying the staples into the tissue, in some instances, thetissue thickness compensator 220 may move the staples relative to oraway from their preferred positions. Moreover, in the event that thetissue thickness compensator 220 were to be removed from the cartridge210 prior to the staples being deployed, the cartridge 210 may no longerbe suitable for its originally intended use. In view of the foregoing,as discussed in greater detail below, the end effector 200 may include alockout configured to prevent the firing member 240 and/or the sled 230from being advanced distally to deploy the staples in the event that thetissue thickness compensator 220 is removed from, or becomes at leastpartially dislodged from, the cartridge body 214 prior to the staplesbeing deployed.

Referring again to FIGS. 44-46, the tissue thickness compensator 220 cancomprise, one, a body 221 configured to be captured by the staples and,two, a loop, or tether, 222 extending from the body 221. In variousinstances, referring primarily to FIG. 47, the loop 222 can compriseends which are at least partially embedded in the body 221 and anintermediate portion extending between the ends which can be releasablyengaged with the sled 230. In certain instances, the loop 222 cancomprise a suture or flexible thread, for example. In some instances,the loop 222 can be comprised of a bioabsorbable material and/or abiocompatible material, for example. Referring primarily to FIG. 48, thesled 230 can include a longitudinal body portion 236, a hook 238extending from the body portion 236, and a slot 237 defined between thebody portion 236 and the hook 238. As illustrated in FIG. 48, the loop222 is positioned within the slot 237 when the tissue thicknesscompensator 220 is positioned over the cartridge deck 211 and the sled230 and the firing member 240 are in an unfired position. As alsoillustrated in FIG. 48, a distal projection 244 extending from thefiring member 240 is positioned against and/or above a support shoulder234 defined on the sled 230 which holds the firing member 240 in anunlocked position, i.e., in a position in which the distal movement ofthe firing member 240 will not be impeded, or at least substantiallyimpeded, by a lockout shoulder 212 defined in the end effector 200 whena firing motion is applied to the firing member 240. Thus, when the sled230 holds the firing member 240 in its unlocked position, referring toFIG. 49, the firing member 240 will slide past the lockout shoulder 212to advance the sled 230 distally, fire the staples removably storedwithin the cartridge body 214, and incise the tissue thicknesscompensator and the tissue positioned within the end effector 200 with aknife edge 242. As illustrated in FIG. 49, the loop 222 can slide out ofthe slot 237 defined in the sled 230 when the sled 230 is advanceddistally.

In the event that the tissue thickness compensator 220 is removed fromthe cartridge 210 or substantially moved from a suitable position overthe deck 211 of the cartridge 210, referring now to FIG. 50, the tissuethickness compensator 220 can pull the sled 230 distally such that thefiring member 240 is no longer supported by the sled 230. Moreparticularly, the loop 222 of the tissue thickness compensator 220positioned within the slot 237 can pull the sled 230 distally from itsunfired position such that the support shoulder 234 is no longerpositioned under the distal projection 244 of the firing member 240. Insuch circumstances, the firing member 240 may shift downwardly into alocked position wherein the distal movement of the firing member 240 canbe impeded by the lockout shoulder 212. In certain circumstances, theend effector 200 can further include a biasing member, such as a spring,for example, which can bias the firing member 240 into its lockedcondition. When the firing member 240 is in its locked condition, thefiring member 240 cannot be moved distally to advance the sled 230, firethe staples from the cartridge body 210, and/or incise the tissuecaptured within the end effector 200. Although the sled 230 may beadvanced distally when the tissue thickness compensator 220 is removedfrom the cartridge 210, the sled 230, in various circumstances, may notbe advanced sufficiently to deploy the staples from the cartridge 210.When the user of the surgical instrument recognizes that the firingmember 240 is in a locked-out condition, the user can remove the staplecartridge 210 from the end effector 200 and replace it with a staplecartridge 210, for example, in which the tissue thickness compensator220 is correctly positioned over the deck 211 and the sled 230 has notbeen advanced distally from its unfired position. Other embodiments arecontemplated in which a staple cartridge is not removable from the endeffector; in such embodiments, the end effector may be entirely replacedin the event that the tissue thickness compensator is removed from thestaple cartridge and/or the firing member enters into a locked-outcondition.

Turning now to FIGS. 51-53, a staple cartridge 310 can include acartridge body 314 and a sled 330 movably positioned within thecartridge body 314. Similar to the above, the cartridge body 314 caninclude a plurality of fastener cavities, such as fastener cavities 316,for example, and a longitudinal slot, such as knife slot 318, forexample, defined therein. The sled 330 can include a central bodyportion 336 slidably positioned within the knife slot 318 and a hook 338extending from the central body portion 336. Referring primarily to FIG.51, a tissue thickness compensator 320 of the cartridge 310 can includea body portion 321 and a catch 322 extending from the body portion 321wherein the catch 322 can be releasably retained in a slot 337 definedbetween the hook 338 and the central body portion 336 when the sled 330is in its unfired, or unadvanced, position. Similar to the above, thecatch 322 can include ends 323 mounted within the body 321 and canextend proximally from the body 321 of the tissue thickness compensator320 wherein, in the event that the tissue thickness compensator 320 isremoved from the cartridge body 314, for instance, the catch 322 canpull the sled 330 distally such that a support shoulder 334 defined inthe central body portion 336 is no longer able to support a firingmember, such as firing member 240, for example, thereon and such thatthe firing member may enter a locked out state. In various instances, auser of the surgical instrument may attempt to reassemble or repositionthe tissue thickness compensator 320 over the deck 311 of the cartridgebody 314; however, the firing member 340 will still remain in a lockedout condition as the repositioning of the tissue thickness compensator320 will not reset the sled 330. Thus, such an arrangement can preventthe cartridge 310 from being used if it has been previously tamperedwith.

In various instances, referring again to FIGS. 51-53, at least a portionof the hook 338 extending from the central portion 336 of the sled 330and/or the slot 337 defined therebetween can extend above the deck 311.In certain instances, at least a portion of the hook 338 extending fromthe central portion 336 of the sled 330 and/or the slot 337 definedtherebetween can extend above the knife slot 318. In such embodiments,the catch 322 can be easily slid into the slot 337 when the tissuethickness compensator 320 is assembled to the cartridge body 314. Incertain instances, the catch 322 can be positioned above or against thedeck surface 311 of the cartridge body 314. In various instances,referring primarily to FIG. 53, the cartridge body 314 can include arecess or pocket 319 defined therein within which the hook 338 can bepositioned when the sled 330 is in its unfired, or unadvanced, position.In such an embodiment, the top of the hook 338 may be positioned belowthe deck surface 311. In various instances, the pocket 319 can furtherinclude one or more ramped surfaces 313 which are defined in the distalend of the pocket 319 and extend downwardly from the deck surface 311.In some instances, the catch 322 can abut the ramped surfaces 313 whenthe sled 330 is advanced distally and, in such circumstances, the hook338 can then separate from the catch 322. In various instances, therecess 319 can be configured to facilitate the assembly of the catch 322to the sled 330 when the tissue thickness compensator 320 is assembledto the cartridge body 314. In various embodiments, the slot 337 canextend longitudinally and can include a closed distal end an openproximal end wherein the catch 322 can be slid into the slot 337 fromthe open proximal end. In the event that the tissue thicknesscompensator 320 is not prematurely removed or dislodged from thecartridge 314, the sled 330 can be advanced distally such that the catch322 exits the slot 337 through the distal end thereof and such thatramps 332 defined on the sled 330 can eject the staples from the staplecartridge 310.

In various instances, a tissue thickness compensator can be adhered to asled utilizing at least one adhesive. In such instances, the adhesiveattachment between the tissue thickness compensator and the sled can bestrong enough to permit the tissue thickness compensator to pull thesled distally in the event that the tissue thickness compensator isremoved from the cartridge. When the sled is advanced distally by thefiring member as part of the firing stroke, the adhesive attachmentbetween the tissue thickness compensator and the sled may fail therebypermitting the sled to slide distally relative to the tissue thicknesscompensator. In various instances, a tissue thickness compensator can bebonded to a sled utilizing a heat steak process and/or a thermoformprocess. In such instances, the bond between the tissue thicknesscompensator and the sled can be strong enough to permit the tissuethickness compensator to pull the sled distally in the event that thetissue thickness compensator is removed from the cartridge. When thesled is advanced distally by the firing member as part of the firingstroke, the bond between the tissue thickness compensator and the sledmay fail thereby permitting the sled to slide distally relative to thetissue thickness compensator.

In some instances, a loop, a catch, and/or tag, for example, can beintegrally formed with a tissue thickness compensator. In variousinstances, the loop, catch, and/or tag, for example, can comprise aunitary piece of material with the tissue thickness compensator. In someinstances, an additional layer can be attached to the tissue thicknesscompensator. This layer, in various instances, can comprise a mountingportion engaged with the sled.

Turning now to FIG. 54, a sled 430 can include, similar to the above, acentral body portion 436 and, in addition, a plurality of ramps 432which are configured to eject staples removably stored within acartridge body, for example. Also similar to the above, the body portion436 can include a hook 438 extending therefrom wherein a slot 437 can bedefined between the body portion 436 and the hook 438. In certaininstances, the slot 437 can include a closed distal end 437 a and anopen proximal end 437 d. In various instances, the slot 437 can furtherinclude a first portion 437 b extending in a first direction and asecond portion 437 c extending in a second direction. In certaininstances, the first portion 437 b can extend along a longitudinal axisand the second portion 437 c can extend along a second axis which istransverse to the longitudinal axis. In at least one such instance, thesecond portion 437 c can extend at an angle relative to the firstportion 437 b.

Turning now to FIGS. 55-58, a sled assembly 530 can include a firstportion 535 and, in addition, a second portion 536 which is movablerelative to the first portion 535 between an unlocked position (FIGS. 55and 57) and a locked position (FIGS. 56 and 58). The first portion 535can include, one, a central portion configured to slide within alongitudinal slot, such as a knife slot 518 defined in a staplecartridge 510, for instance, and, two, a plurality of ramps 532configured to eject staples removably stored within the cartridge 510.The central portion of the first portion 535 can include a first slot533 a and a second slot 533 b defined therein. The first slot 533 a andthe second slot 533 b can be configured to receive pins 531 a and 531 b,respectively, extending from the second portion 536. The first pin 531 acan be configured to slide within the first slot 533 a and the secondpin 531 b can be configured to slide within the second slot 533 b inorder to permit the second portion 536 to rotate relative to the firstportion 535. In various instances, the first pin 531 a can be closelyreceived within the first slot 533 a such that the first slot 533 a canconstrain the motion of the first pin 531 a along a first path and,similarly, the second pin 531 b can be closely received within thesecond slot 533 b such that the second slot 533 b can constrain themotion of the second pin 531 b along a second path. Referring primarilyto FIG. 57, the second portion 536 of the sled assembly 530 can comprisean arm configured to slide within the knife slot 518 wherein the arm caninclude a support shoulder 534 defined on the proximal end thereof and ahook 538 defined on the distal end thereof. Similar to the above, thesupport shoulder 534 can be configured to support a firing member 240,for example, in an unlocked position when the sled assembly 530 is in aproximal, unfired position and the tissue thickness compensator 220, forinstance, is positioned over and/or against the deck surface 511 of thecartridge 510. Also similar to the above, the hook 538 can be configuredto releasably hold the loop 222 of the tissue thickness compensator 220such that, in the event that the tissue thickness compensator 220 wereto be removed from and/or substantially displaced relative to thecartridge body, the loop 222 could pull on the second portion 536 topivot the second portion 536 into its locked position as illustrated inFIG. 58. In such a locked position of the second portion 536, thesupport shoulder 534 may no longer support the distal projection 244 ofthe firing member 240 and the firing member 240 can drop downwardly intoits locked position. As depicted in FIG. 58, the rotation of the secondportion 536 into its locked position can move the support shoulder 534distally and/or downwardly away from the firing member 240. As alsodepicted in FIG. 58, the firing member 240 can include a lock 541extending from opposite sides thereof which can be configured to abutthe lockout shoulder 212 when the firing member 240 is in its lockedposition. When the firing member 240 is held in its unlocked position bythe sled assembly 530, the locks 541 may not contact the lockoutshoulder 212 and the firing member 240 can be advanced through thecartridge 510.

In various instances, as discussed above, a portion of a staple-drivingsled may extend above the deck surface of a cartridge body. Forinstance, referring again to FIGS. 52 and 54, the hook 338 of the sled330 (FIG. 52) and/or the hook 438 of the sled 430, for example, canextend above the deck surface. In such instances, the hook 338 and/orthe hook 438 can translate distally above the deck surface and, in someinstances, contact the tissue thickness compensator positioned againstor above the deck surface. In certain instances, the hook 338 and/or thehook 438 can lift the tissue thickness compensator upwardly away fromthe cartridge body and facilitate the progressive release of the tissuethickness compensator from the cartridge. For instance, the hook 338and/or the hook 438 can begin at the proximal end of the tissuethickness compensator and move toward the distal end of the tissuethickness compensator in order to initially lift the proximal end of thetissue thickness compensator and then progressively lift it away fromthe cartridge deck until the distal end of the tissue thicknesscompensator is eventually lifted away from the cartridge body. In otherinstances, as discussed in greater detail further below. it may bepreferable for the portion of the sled contacting the tissue thicknesscompensator to deflect downwardly and/or otherwise not disturb thetissue thickness compensator as the sled is advanced distally.

Turning now to FIGS. 59 and 60, a staple cartridge 610 can include acartridge body 614, a tissue thickness compensator 620 releasablyretained to the cartridge body 614, and a sled 630 configured tolongitudinally traverse the cartridge body 614 and eject staplesremovably stored therein. The sled 630 can include a main body portion635 having a plurality of ramp surfaces defined thereon, a supportshoulder 634, and an arm 636 extending from the body portion 635. Invarious instances, the arm 636 can be assembled to the main body portion635. For instance, the arm 636 can include a first end embedded in themain body portion 635 and a second end including a hook 638, forexample. In various instances, the arm 636 can comprise a cantileverbeam extending from the main body portion 635. In certain instances, thearm 636 can be comprised of a resilient and/or flexible material, forexample. Similar to the above, a slot 637 can be defined between thehook 638 and the arm 636 which can be configured to releasably hold aportion of the tissue thickness compensator 620 when the sled 630 is inits proximal, unfired position. In the event that the tissue thicknesscompensator 620 is pulled off of the cartridge body 614, for example,the tissue thickness compensator 620 can pull the sled 630 distally awayfrom a firing member so that the firing member enters into a locked outcondition.

In various instances, further to the above, at least a portion of thearm 636, such as the hook 638, for example, can extend above the decksurface 611 of the cartridge body 614. In certain instances, the arm 636can be engaged with a loop, for example, extending from the tissuethickness compensator 620 when the sled 630 is in its proximal position(FIG. 59) and, as the sled 630 is advanced distally, the arm 636 candisengage from the loop. As the sled 630 is advanced distally, incertain instances, the arm 636 can contact the body portion 621 of thetissue thickness compensator 620 and flex downwardly. In variousinstances, the deflected arm 636 can slide within a longitudinal knifeslot 618 defined in the cartridge body 614 as the sled 630 is advanceddistally. In some instances, referring to FIG. 60, the distal end of thelongitudinal slot 618 can be defined by a nose wall, or roof, 619wherein, when the sled 630 reaches a distal end 617 of the cartridge610, the arm 636 can slide under the nose wall 619 such that the firingstroke of the end effector can be completed. In some instances, the arm636 may not be deflected, or substantially deflected, downwardly by thetissue thickness compensator 620 wherein, when the arm 636 reaches theend of the longitudinal slot 618, the arm 636 can contact the nose wall618 and flex downwardly in order to slide thereunder as illustrated inFIG. 60. In various circumstances, as a result, the flexible arm 636 canpermit the firing stroke to be completed and for the sled 630 to beparked at the distal end of the cartridge.

Turning now to FIG. 61, a sled, such as sled assembly 730, for example,can include a main body portion 735 and a movable arm 736. Similar tothe above, the main body portion 735 can include one or morestaple-driving ramps 732 and a support shoulder 734 configured tosupport a firing member in an unlocked position, as described above. Thearm 736 can include a first end pivotably and/or rotatably mounted tothe main body portion 735 and a second end including a hook 738configured to be releasably engaged with a tissue thickness compensator,as described above. When the sled assembly 730 is advanced distally, thehook 738 can detach from the tissue thickness compensator; however, theupper surface of the hook 738 can remain in contact with the bottomsurface of the tissue thickness compensator. In such circumstances, thearm 736 can pivot downwardly into the knife slot 318, for example, inorder to slide under the tissue thickness compensator. Moreparticularly, the arm 736 can pivot from a raised, or uppermost,position (FIG. 61) to a lowered, or depressed, position. In variousinstances, the sled assembly 730 can further include a resilient biasingmember, such as a spring 731, for example, configured to bias the arm736 into its raised position. When the arm 736 has been rotateddownwardly into its lowered position, the spring 731 can apply a biasingforce to the arm 736 which is transmitted into the tissue thicknesscompensator. In certain instances, the spring 731 can be positionedintermediate the arm 736 and a frame portion 733 defined on the mainbody portion 735. In various instances, the spring 731 can comprise acantilever spring or leaf spring, for example, extending from the arm736. When the arm 736 is pushed downwardly, the cantilever spring can beconfigured to flex and/or slide along the frame portion 731, forinstance. In various embodiments, the main body portion 735 can furtherinclude a stop shoulder 739, for example, which can limit the upwardrotation, or travel, of the arm 736. In any event, similar to the above,the arm 736 can be configured to rotate downwardly when it contacts theroof 619 and permit the firing stroke to be completed.

In various instances, a staple can comprise a base and one or more legsextending from the base. In certain instances, a staple can comprise abase including a first end and a second end, a first leg extending fromthe first end, and a second leg extending from the second end. In someinstances, the staple can be formed from a continuous wire whichcomprises the first leg, the base, and the second leg. A first end ofthe continuous wire can comprise a tip of the first staple leg and asecond end of the continuous wire can comprise a tip of the secondstaple leg. One such staple, i.e., staple 800, is depicted in FIG. 62,for example. The staple 800 can include a base 802, a first staple leg804 extending from a first end of the base 802, and a second staple leg804 extending from a second end of the base 802. The first staple leg804 can include a first tip 806 and, similarly, the second staple leg804 can include a second tip 806. In various instances, the tips 806 canbe configured to penetrate tissue, such as tissue T depicted in FIG. 62,for example. In some instances, the tips 806 can be sharp and can beformed by a coining process, for example. In various embodiments, thewire can be comprised of titanium and/or stainless steel, for example.

In various embodiments, the staple 800 can be U-shaped, or at leastsubstantially U-shaped, for example, when it is in its unformedconfiguration. In such embodiments, the legs 804 of the staple 800 canbe parallel, or at least substantially parallel, to one another.Moreover, in such embodiments, the legs 804 can be perpendicular, or atleast substantially perpendicular, to the base 802. In certainembodiments, the staple 800 can be V-shaped, or at least substantiallyV-shaped, for example, when it is in its unformed configuration. In suchembodiments, the legs 804 of the staple 800 are not parallel to oneanother; rather, the legs 804 can extend in non-parallel directions.Moreover, in such embodiments, one or both of the legs 804 are notperpendicular to the base 802 wherein one or both of the legs 804 canextend in directions which are oblique to the base 802. In variousinstances, the legs 804 may extend, or splay, outwardly with respect toa center or midline of the staple. In any event, the staple 800 can beremovably stored within a staple cartridge, ejected from the staplecartridge to penetrate tissue, as illustrated in FIG. 62, and thencontact an anvil positioned on the opposite side of the tissue. Theanvil can be configured to deform the staple 800 into any suitableshape, such as a B-form configuration, for example, as also illustratedin FIG. 62. Various formed staple configurations, such as the B-formconfiguration, for example, can define a tissue entrapment area, such astissue entrapment area 807, for example, configured to entrap tissuewithin the staple.

As discussed above, a staple can be removably stored within a cavitydefined in a cartridge body. A cartridge body 810 is depicted in FIG. 63which can include one or more staple cavities 812 defined therein.Referring to FIGS. 63, 68, and 69, each staple cavity 812 can include afirst end 814 and a second end 814. In certain embodiments, such asembodiments including a longitudinal end effector, for example, thefirst end 814 can comprise a proximal end of the staple cavity 812 andthe second end 814 can comprise a distal end of the staple cavity 812.In various instances, a staple can be positioned within a staple cavity812 such that a first leg 804 of the staple 800 is positioned in thefirst end 814 of the staple cavity 812 and a second leg 804 ispositioned in the second end 814. In various instances, a staple cavitywidth can be defined between the ends 814 of a staple cavity 812. Thebase 802 of a staple can be defined by a base width which can be equalto or shorter than the staple cavity width, for example. In certaininstances, a staple can comprise a staple width which can be definedbetween the tips 806 of the staple legs 804. In some embodiments, thestaple width can be equal to the staple cavity width. In variousembodiments, the staple width can be wider than the staple cavity width.In such embodiments, the legs 804 can be in contact with the ends 814 ofa staple cavity 812 and can be resiliently biased inwardly by the ends814 when the staple is positioned within the staple cavity 812. When thestaple is lifted upwardly out of the staple cavity 812, the legs 804 canresiliently splay outwardly as they emerge from the staple cavity 812.For example, the staple can be positioned within the staple cavity 812such that the tips 806 of the staple legs 804 do not extend above a topsurface, or deck, of the cartridge body 810 when the staple is in itsunfired, or uplifted, position. In such a position, the tips 806 can bepositioned flush with or recessed below the deck 811 of the cartridgebody 810. Alternatively, the tips 806 of the legs 804 can at leastpartially extend above the deck 811 of the cartridge body 810. In anyevent, as the staple is lifted upwardly, the staple tips 806 can emergeabove the deck 811 and splay outwardly as the legs 804 emerge from thecavity 812. At some point during the lifting of the staple, the legs 804may no longer be in contact with the ends 814 of the staple cavity 812and the legs 804 may no longer be biased inwardly by the sidewalls ofthe staple cavity 812.

In various instances, an anvil can include one or more pocketsconfigured to receive the tips 806 of the staple legs 804 as the staple800 is ejected from the staple cartridge. The anvil pockets can beconfigured to turn, or bend, the staple legs 804 inwardly toward oneanother, for example. In other instances, the anvil pockets can beconfigured to turn, or bend, the staple legs 804 outwardly away from oneanother, for example. In some instances, however, one or more of thestaple legs of a staple may miss a staple pocket and may not be properlydeformed. In certain instances, one or more of the staple legs may notcontact the anvil and may not be deformed at all. In either event, thestaple may not properly capture and/or retain the tissue within itstissue entrapment area. Moreover, the misformed or unformed staple maynot be able to apply a desired compressive pressure to the tissue. Insome instances, the misformed or unformed staple may not be retained inthe tissue and can become dislodged from the tissue.

Referring again to FIG. 62, the staple 800, and/or various other staplesdisclosed herein, can include one or more barbs extending therefrom. Invarious instances, the barbs can be configured to engage tissue capturedwithin and/or surrounding the staple. In certain instances, the barbscan assist in retaining the staple within the tissue, especially whenthe staple has been misformed or unformed. The staple 800 can includebarbs extending from one or both of the legs 804. For instance, each leg804 can include one or more barbs 808 which face outwardly from thecenter of the staple 800 and/or one or more barbs 809 which faceinwardly toward the center of the staple 800, for example. In certaininstances, the barbs 808 can extend away from the tissue entrapment area807 and/or the barbs 809 can extend toward or into the tissue entrapmentarea 807. As depicted in FIG. 62, both of the staple legs 804 of staple800 can include barbs 808 and barbs 809. In some instances, the staplelegs 804 can include barbs 808, but not barbs 809. A staple 820 isdepicted in FIG. 63 which includes barbs 808, but not barbs 809. In someinstances, the staple legs 804 can include barbs 809, but not barbs 808.Staples 830, 840, 850, 860, and 870 are depicted in FIGS. 64, 65, 66,67, and 68, respectively, which include barbs 809, but not barbs 808. Insome embodiments, a first leg 804 of a staple can include barbs 808while a second leg 804 of the staple can include barbs 809, for example.

In various instances, the legs 804 and the base 802 of a staple candefine a staple plane when the staple is in an unformed configuration.The barbs 808 can extend outwardly from the legs 804 within such astaple plane. Similarly, the barbs 809 can extend inwardly from the legs804 within such a plane. In some instances, a staple can include barbswhich extend laterally with respect to such a staple plane. Otherembodiments are envisioned in which the legs 804 and the base 802 do notlie within, or entirely lie within, a single plane. In such embodiments,the barbs can extend in any suitable direction. In various embodiments,referring now to FIG. 67, a staple, such as staple 860, for example, caninclude barbs 803 extending from the base 802. In various instances, thebarbs 803 can extend inwardly toward the tissue entrapment area 807 ofthe staple 860. In certain instances, the barbs 803 can extend outwardlyaway from the tissue entrapment area 807. As illustrated in FIG. 67, thebarbs 803 can extend within a staple plane defined by the legs 804 andthe base 802. In certain instances, the barbs 803 can extend laterallywith respect to such a staple plane. Various exemplary barbconfigurations are discussed in greater detail further below.

In various instances, a staple leg 804 can comprise an array of barbs808 which extends along the entire length thereof. In some instances, astaple leg 804 can comprise an array of barbs 808 which extends alongless than the entire length thereof. By way of example, referring toFIG. 62, the legs 804 of the staple 800 each comprise an array of barbs808 which extends along less than the entire length of the legs 804.Similarly, referring to FIG. 63, the legs 804 of the staple 820 eachcomprise an array of barbs 808 which extends along less than the entirelength of the legs 804. With regard to the staple 800, for example, anarray of barbs 808 can extend along each of the legs 804 from the base802 of the staple 800 toward the tips 806 of the legs 804. Asillustrated in FIG. 62, the arrays of barbs 808 may not extend to thetips 806 of the legs 804. In various instances, the arrays of barbs 808can extend along half, or approximately half, the lengths of the legs804, for example; however, any suitable length of the barb arrays couldbe utilized. For instance, the arrays of barbs 808 can extend along lessthan half or more than half of the lengths of the legs 804. In someembodiments, an array of barbs 808 can extend along each of the legs 804from the tips 806 of the legs 804 toward the base 802. In suchembodiments, the array of barbs 808 may not extend to the base 802. Insome embodiments, a leg 804 can comprise an array of barbs 808 whichdoes not extend to the tip 806 of the leg 804 or the base 802. Incertain embodiments, a leg 804 can comprise more than one array of barbs808.

In various instances, further to the above, a staple leg 804 cancomprise an array of barbs 809 which extends along the entire lengththereof. By way of example, referring to FIG. 64, the legs 804 of thestaple 830 each comprise an array of barbs 809 which extends along theentire length of the legs 804. In some instances, a staple leg 804 cancomprise an array of barbs 809 which extends along less than the entirelength thereof. By way of example, referring to FIG. 65, the legs 804 ofthe staple 840 each comprise an array of barbs 809 which extends alongless than the entire length of the legs 804. Similarly, referring toFIG. 68, the legs 804 of the staple 870 each comprise an array of barbs809 which extends along less than the entire length of the legs 804.With regard to the staple 840, for example, an array of barbs 809 canextend along each of the legs 804 from the base 802 of the staple 840toward the tips 806 of the legs 804. As illustrated in FIG. 65, thearrays of barbs 809 may not extend to the tips 806 of the legs 804. Invarious instances, the arrays of barbs 809 can extend along half, orapproximately half, the lengths of the legs 804, for example; however,any suitable length of the barb arrays could be utilized. For instance,the arrays of barbs 809 can extend along less than half or more thanhalf of the lengths of the legs 804. In some embodiments, an array ofbarbs 809 can extend along each of the legs 804 from the tips 806 of thelegs 804 toward the base 802. In such embodiments, the array of barbs809 may not extend to the base 802. In some embodiments, as illustratedin FIG. 66, a leg 804 can comprise an array of barbs 809 which does notextend to the tip 806 of the leg 804 or the base 802. In certainembodiments, a leg 804 can comprise more than one array of barbs 809.

Various barb configurations are depicted in FIGS. 70-73, although anysuitable barb configuration could be utilized. Referring to FIG. 70, astaple leg 804 can include at least one barb 809, for example. Invarious instances, the barb 809 can comprise a prong. The prong caninclude a first surface 809 a and a second surface 809 b which canextend from the perimeter 805 of the staple leg 804. The first surface809 a can comprise an inclined surface, a convex surface, and/or aconcave surface, for example. The second surface 809 b can comprise aflat, or an at least substantially flat, surface, for example. Invarious instances, the first surface 809 a and the second surface 809 bcan converge at an edge 809 c, for example. The barb 809 can be formedutilizing any suitable process. For instance, the barb 809 can be formedutilizing a stamping process. In at least one embodiment, a forming die,for example, can be utilized to strike the perimeter 805 of the wirecomprising the leg 804 in order to upset, or disturb, enough material tocreate the barb 809. In various instances, a barb can comprise anysuitable nib or spur, for example. In various embodiments, the barb 809can be tapered. In various instances, the barb 809 can include a baseadjacent to the perimeter 805 which is thicker than a tip of the barb809.

Referring now to FIGS. 68, 69, 71, and 71A, a staple leg 804 can includeat least one barb 879, for example. In at least one embodiment, the barb879 can extend around a portion of the perimeter 805 of the staple leg804. In various instances, the barb 879 can include a first surface 879a and a second surface 879 b which can extend from the perimeter 805 ofthe staple leg 804. The first surface 879 a can comprise an inclinedsurface, a convex surface, and/or a concave surface, for example. Thesecond surface 879 b can comprise a flat, or an at least substantiallyflat, surface, for example. In various instances, the first surface 879a and the second surface 879 b can converge at an edge 879 c, forexample. In various instances, the edge 879 c can be arcuate, forexample. The barb 879 can be formed utilizing any suitable process. Forinstance, the barb 879 can be formed utilizing a stamping process. In atleast one embodiment, a forming die, for example, can be utilized tostrike the perimeter 805 of the wire comprising the leg 804 in order toupset, or disturb, enough material to create the barb 879. Referringprimarily to FIG. 71A, the wire comprising the leg 804 can be defined bya diameter 801 and the barb 879 can be defined by a diameter which islarger than the diameter 801. Correspondingly, the wire comprising theleg 804 can be defined by a radius and the barb 879 can be defined by aradius which is larger than the wire radius. In various embodiments, thebarb 879 can be tapered. In various instances, the barb 879 can includea base adjacent to the perimeter 805 which is thicker than a tip of thebarb 879.

Referring now to FIG. 72, a staple leg 804 can include at least one barb889, for example. In at least one embodiment, the barb 889 can extendaround the entirety of the perimeter 805 of the staple leg 804. Invarious instances, the barb 889 can include a first surface 889 a and asecond surface 889 b which can extend from the perimeter 805 of thestaple leg 804. The first surface 889 a can comprise an inclinedsurface, a convex surface, and/or a concave surface, for example. Thesecond surface 889 b can comprise a flat, or an at least substantiallyflat, surface, for example. In various instances, the first surface 889a and the second surface 889 b can converge at an edge 889 c, forexample. In various instances, the edge 889 c can be arcuate, forexample. The barb 889 can be formed utilizing any suitable process. Forinstance, the barb 889 can be formed utilizing a stamping process. In atleast one embodiment, a forming die, for example, can be utilized tostrike the perimeter 805 of the wire comprising the leg 804 in order toupset, or disturb, enough material to create the barb 889. The wirecomprising the leg 804 can be defined by a wire diameter and the barb889 can be defined by a diameter which is larger than the wire diameter.Correspondingly, the wire comprising the leg 804 can be defined by aradius and the barb 889 can be defined by a radius which is larger thanthe wire radius. In various embodiments, the barb 889 can be tapered. Invarious instances, the barb 889 can include a base adjacent to theperimeter 805 which is thicker than a tip of the barb 889.

Referring now to FIG. 73, a staple leg 804 can include at least one barb899, for example. In various instances, the barb 899 can comprise aprong. The prong can include a first surface 899 a and a second surface899 b which can extend from the perimeter of the staple leg 804. Thefirst surface 899 a can comprise an inclined surface, a convex surface,and/or a concave surface, for example. The second surface 899 b cancomprise a flat, or an at least substantially flat, surface, forexample. In various instances, the first surface 899 a and the secondsurface 899 b can converge at an edge 899 c, for example. The barb 899can be formed utilizing any suitable process. For instance, the barb 899can be formed utilizing a stamping process. In at least one embodiment,a forming die, for example, can be utilized to strike the perimeter ofthe wire comprising the leg 804 in order to upset, or disturb, enoughmaterial to create the barb 899. In various embodiments, the wirecomprising the staple can include one or more flat sides. In at leastone embodiment, the wire can include opposing flat sides 895, forexample. In at least one such embodiment, the flat sides 895 can beformed into a cylindrical wire. In some instances, the wire can retainone or more cylindrical surfaces in addition to the flat sides 895. Invarious instances, a barb can comprise any suitable nib or spur, forexample. In various embodiments, the barb 899 can be tapered. In variousinstances, the barb 899 can include a base adjacent to the perimeter ofthe leg 804 which is thicker than a tip of the barb 899.

In various instances, the legs of a staple can define a staple plane.The base of the staple may or may not be positioned within the stapleplane. In either event, one or more barbs extending from the legs and/orthe base may extend within and/or extend parallel with respect to thestaple plane. In some instances, one or more barbs extending from thelegs and/or the base can extend outwardly from the staple plane. One ormore barbs extending from the legs and/or the base can extendtransversely with respect to the staple plane. In various instances, abarb can extend circumferentially around a staple leg. Such a barb canextend within and outwardly from the staple plane. In some instances, abarb can extend around the entire circumference of a staple leg. Incertain instances, the barb can extend less than 360 degrees around astaple leg. A barb extending within a staple plane can readily controltissue within the staple plane. A barb extending outwardly from a stapleplane can readily control tissue outside of the staple plane. A staple,and/or a staple leg, can include one or more barbs extending within thestaple plane and one or more barbs extending outwardly from the stapleplane.

Referring again to FIG. 62, the barbs extending from a staple leg 804can be configured to retain the staple leg 804 within tissue. As outlineabove, the staple legs 804 may be malformed and/or unformed by an anvilin certain instances and, owing to the barb, or barbs, extendingtherefrom, the staple leg 804 may still be retained in the tissue. Invarious instances, the barbs can be configured to trap tissue within thetissue entrapment area of the staple. In certain instances, the barbscan be configured to hold the tissue against the base 802. In suchinstances, the barbs can apply a compressive force or pressure to thetissue. As discussed above in connection with the embodiments depictedin FIGS. 70-73, a barb can comprise an inclined, convex, and/or concavetop surface, such as surfaces 809 a, 879 a, 889 a, and/or 899 a, forexample. The top surfaces of the barbs can be configured to facilitatethe insertion of the barbs and the staple legs 804 into and/or throughthe tissue. As also discussed above in connection with the embodimentsdepicted in FIGS. 70-73, a barb can comprise a flat, or at leastsubstantially flat, bottom surface, such as surfaces 809 b, 879 b, 889b, and/or 899 b, for example. The bottom surfaces of the barbs can beconfigured to inhibit the removal of the barbs and the staple legs 804from the tissue. As a result of the above, in certain circumstances, thetop surfaces of the barbs can be configured to pierce the tissue whilethe bottom surfaces of the barbs can be configured to abut the tissue.In various circumstances, the tips 806 of the staple legs 804 can beconfigured to puncture a hole in the tissue while the staple legs 804and the barbs extending therefrom can be configured to resilientlyexpand the hole such that such that the tissue can flow around the barbsas the staple legs 804 are being pushed through the tissue and flow backunderneath the bottom surfaces of the barbs.

In certain embodiments, a first barb can extend from a first leg 804 ofthe staple and a second barb can extend from a second leg 804 of thestaple. In various instances, the first barb and the second barb can belocated the same, or at least substantially the same, distance betweenfrom the base 802. In certain instances, the first barb and the secondbarb can be located the same, or at least substantially the same,vertical distance from the base 802. As discussed above, a staple leg804 can include an array of barbs extending along the length of thestaple leg 804. In various embodiments, referring primarily to FIG. 62,a staple can include a first leg 804 including a first array of barbsand a second leg 804 including a second array of barbs wherein the firstarray of barbs and the second array of barbs can be configured toco-operatively hold the staple within the tissue. In variousembodiments, a barb from the first array and a barb from the secondarray can comprise a pair of barbs configured to engage tissue at thesame vertical distance from the base 802, for example. In variousinstances, a staple can comprise more than one pair of barbs. In certaininstances, each of the barb pairs can be configured to engage the tissueat a different vertical distance from the base 802. In suchcircumstances, a staple can be suitable for use with different tissuethicknesses. For instance, when a staple is used to staple thin tissue,one pair of barbs, or less than all of the barb pairs, may engage thethin tissue. If that staple were used to staple thick tissue, however,additional barb pairs, or all of the barb pairs, may engage the tissue.In certain embodiments, the barbs extending from the legs 804 can bearranged in a manner in accordance with the tissue thickness, or rangeof tissue thicknesses, that can be stapled by the staple. For instance,referring again to FIG. 62, the barbs 808 and 809 can be selectivelypositioned along the legs 804 such that they are positioned withinand/or adjacent to the tissue captured within the staple. In certaininstances, the portions of the staple legs 804 that are deformed by, orcome into contact with, an anvil may not include barbs extendingtherefrom. In at least some instances, an array of barbs extending fromthe inwardly-facing side of the staple legs 804 may be longer than anarray of barbs extending from the outwardly-facing side of the staplelegs 804. In other instances, an array of barbs extending from theinwardly-facing side of the staple legs 804 may be shorter than an arrayof barbs extending from the outwardly-facing side of the staple legs804. In yet other instances, an array of barbs extending from theinwardly-facing side of the staple legs 804 may be the same length as anarray of barbs extending from the outwardly-facing side of the staplelegs 804.

As discussed above, the barbs extending from the staple legs 804 canassist in retaining the staple within the tissue if the staple legs 804are malformed and/or unintentionally unformed. Certain circumstances arecontemplated, however, where a staple including one or more of the barbsdisclosed herein is inserted into tissue and remains intentionallyunformed. In any event, staples including one or more of the barbsdisclosed herein can be useful in stapling thick tissue. Moreparticularly, in some instances, the presence of thick and/or densetissue between a staple cartridge and an anvil and/or the presence ofthick and/or dense tissue within a staple may prevent the staple frombecoming fully formed or closed. For instance, the staple may not befully closed into a B-form configuration or the staple may not be closedat all. In such instances, the barbs of the unclosed staples may inhibitor prevent the tissue from being pulled out of the staple, for example.An array of barbs extending along the length of a staple leg may permitthe leg to remain retained in the tissue regardless of the thickness ofthe tissue.

Various embodiments are contemplated in which at least one barbedstaple, such as barbed staple 800, for example, are removably storedwithin a staple cartridge, such as the staple cartridge 22000illustrated in FIGS. 10-12, for example. Certain embodiments areenvisioned in which a staple cartridge includes only barbed stapleswhile other embodiments are envisioned which utilize barbed staples andnon-barbed staples. For instance, a first row of staples can comprisebarbed staples while a second row of staples can comprise non-barbedstaples. In some instances, the staples stored within a staple cartridgecan have the same, or essentially the same, unformed height. At leastwith regard to U-shaped and/or V-shaped staples, for example, theunformed height of a staple can be defined as the vertical distancebetween the bottom of the base of the staple and the tips of the staplelegs. Such a measurement can be taken before the staples are insertedinto the staple cartridge, when the staples are removably stored withinthe staple cartridge, and/or before the staples are deformed against theanvil. In some instances, barbed staples arranged in a first row in astaple cartridge can comprise a first unformed height and barbed staplesarranged in a second row in the staple cartridge can comprise a secondunformed height. Barbed staples in a third row in the staple cartridgecan comprise the first unformed height, the second unformed height, or athird unformed height. The first row, the second row, and/or the thirdrow of barbed staples can be positioned on the same side of a knife slotdefined in the staple cartridge or on opposite sides of the knife slot.In use, the barbed staples removably stored in a staple cartridge can beformed to the same formed height or different formed heights. The formedheight of a staple can be defined as the overall vertical distance ofthe staple after it has been deformed against an anvil. At least withregard to a staple that has been deformed into a B-form, for example,the formed height of the staple can be measured between the bottom ofthe base of the staple and the top-most portion of the staple legs. Insome instances, barbed staples arranged in a first row in a staplecartridge can be deformed to a first formed height and barbed staplesarranged in a second row in the staple cartridge can be deformed to asecond formed height. Barbed staples in a third row in the staplecartridge can comprise the first formed height, the second formedheight, or a third formed height. The first row, the second row, and/orthe third row of barbed staples can be positioned on the same side of aknife slot defined in the staple cartridge or on opposite sides of thestaple cartridge. As the reader will appreciate, the staples depicted inFIGS. 10-12 have been deformed to different formed heights. Barbedstaples 800, for example, could be utilized in staple cartridges and/orstapling instruments which create staple rows having different formedheights. A first row of barbed staples 800 could be deformed to a firstformed height and a second row of barbed staples 800 could be deformedto a second formed height. In various instances, a third row of barbedstaples 800 could be deformed to a third formed height. In someinstances, the barbed staples 800 deformed to different heights canbegin with the same, or essentially the same, unformed height. Incertain instances, the barbed staples 800 deformed to different formedheights can begin with different unformed heights. Various structurescan be utilized to form staples to different formed heights. Forinstance, movable drivers supporting the staples can support the staplesat different distances relative to the anvil. In some instances, theanvil can include staple forming pockets having different depths. Invarious instances, a staple driver can include a cradle configured tosupport the base of a staple and push the staple upwardly toward aforming pocket defined in the anvil. The formed height of a staple canbe determined by the distance between the bottom surface of the cradleand the top surface of the forming pocket. U.S. Pat. No. 8,317,070,entitled SURGICAL STAPLING DEVICES THAT PRODUCE FORMED STAPLES HAVINGDIFFERENT LENGTHS, issued on Nov. 27, 2012, is incorporated by referencein its entirety. In certain instances, the deck of a staple cartridgecan include stepped surfaces, as illustrated in FIG. 1. A first row ofstaple cavities can be defined in a first step and a second row ofstaple cavities can be defined in a second step wherein the first stepand the second step can be vertically offset from one another. Forinstance, the first step can be positioned vertically above, or closerto, the anvil than the second step. In certain instances, a wall can bedefined between the first step and the second step. In some instances,the deck of a staple cartridge can comprise a first step, a second steppositioned vertically above the first step, and a third step positionedvertically above the second step. Various embodiments are envisioned inwhich the deck of a staple cartridge includes any suitable number ofsteps and any suitable number of walls between the steps. A first row ofstaple cavities can be defined in the first step, a second row of staplecavities can be defined in the second step, and/or a third row of staplecavities can be defined in the third step, for example. The first row ofstaple cavities can include staples having a first unformed height, thesecond row of staple cavities can include staples having a secondunformed height, and/or the third row of staple cavities can includestaples having a third unformed height, for example. Various embodimentsare envisioned in which a staple cartridge includes any suitable numberof staple rows having different unformed heights. The staples in thefirst row of staple cavities can be deformed to a first formed height,the staples in the second row of staple cavities can be deformed to asecond formed height, and/or the third row of staple cavities can bedeformed to a third formed height, for example. Various embodiments areenvisioned in which a staple cartridge includes any suitable number ofstaple rows which are deformed to different formed heights. In additionto or in lieu of having different formed staple heights, an end effectorof a stapling instrument can have different tissue gaps. For instance,referring generally to FIGS. 10 and 11, a gap can be defined between thecartridge deck surface 22011 of a staple cartridge and the anvil tissuecompression surface 10063 of an anvil. This gap can be configured toreceive tissue T. This gap can also be configured to receive a tissuethickness compensator; however, a barbed staple may or may not be usedwith a tissue thickness compensator and the discussion provided withrespect to barbed staples can be applicable in either circumstance. Inany event, the reader will appreciate that the anvil tissue compressionsurface 10063 is stepped. The anvil tissue compression surface 10063comprises a first portion positioned vertically above a second portion.When the anvil and the staple cartridge of an end effector are in aclosed condition, as illustrated in FIG. 11, a first gap distance isdefined between an outer portion of the anvil tissue compression surface10063 and the cartridge deck surface 22011 and a second, different, gapdistance is defined between an inner portion of the anvil tissuecompression surface 10063 and the cartridge deck surface 22011. Thefirst gap distance is illustrated as being larger than the second gapdistance, but it is possible for the first gap distance to be shorterthan the second gap distance. Tissue compressed between the anvil andthe staple cartridge in the shorter gap distance can be compressed morethan tissue in the larger gap distance. The barbs of a barbed staple800, for example, may engage the tissue differently depending on whetherthe tissue is positioned within a shorter tissue gap or a larger tissuegap. More particularly, tissue compressed within a shorter tissue gapmay seek to re-expand more after it is released from an end effectorthan tissue compressed within a larger tissue gap and the barbs of abarbed staple may inhibit or resist this re-expansion, depending ontheir configuration and/or position on the barbs. In other instances,the barbs may be configured and/or positioned so as to not inhibit orresist the re-expansion of the tissue. As the reader will appreciate,anvil tissue compression surface 10063 is stepped and the cartridge decksurface is flat, or at least substantially flat, and, thus, thedifference in tissue gaps defined within the end effector is a functionof the height of the stepped anvil surfaces. Other embodiments areenvisioned. For instance, the anvil tissue compression surface can beflat, or at least substantially flat, and the cartridge deck surface canbe stepped. In other instances, the anvil tissue compression surface andthe cartridge deck surface can both be stepped. In any event, differentgap distances can be defined between the anvil tissue compressionsurface and the cartridge deck surface. While two gap distances havebeen illustrated in FIGS. 10 and 11, more than two gap distances may bepossible, such as three gap distances, for example. With furtherreference to FIGS. 10 and 11, a first longitudinal row of formingpockets can be arranged within a first portion of an end effector havingfirst tissue gap distance and a second longitudinal row of formingpockets can be arranged within a second portion of the end effectorhaving a second tissue gap distance which is different than the firsttissue gap distance. In some instances, the end effector can include athird longitudinal row of forming pockets arranged within a thirdportion of the end effector having a third tissue gap distance which isdifferent than the first tissue gap distance and the second tissue gapdistance. In certain instances, the end effector can include a thirdlongitudinal row of forming pockets arranged within a third portion ofthe end effector having a tissue gap distance which is the same as thefirst tissue gap distance or the second tissue gap distance. The readerwill appreciate that an end effector can have different tissue gapdistances and/or different formed staple heights. An end effector canhave one, the other, or both. In certain instances, shorter formedstaple heights can be associated within shorter tissue gap distanceswhile larger formed staple heights can be associated with larger tissuegap distances. In other instances, shorter formed staple heights can beassociated with larger tissue gap distances while larger formed stapleheights can be associated with shorter tissue gap distances. Further tothe above, a staple can include a U-shape configuration in its unformedstate. A U-shape staple can comprise a base and two staple legsextending from the base wherein the staple legs extend in paralleldirections to each other. Also further to the above, a staple caninclude a V-shape configuration in its unformed state. A V-shapeconfiguration can comprise a base and two staple legs extending from thebase wherein the staple legs extend in directions which are notparallel.

Various embodiments described herein are described in the context oflinear end effectors and/or linear fastener cartridges. Suchembodiments, and the teachings thereof, can be applied to non-linear endeffectors and/or non-linear fastener cartridges, such as, for example,circular and/or contoured end effectors. For example, various endeffectors, including non-linear end effectors, are disclosed in U.S.patent application Ser. No. 13/036,647, filed Feb. 28, 2011, entitledSURGICAL STAPLING INSTRUMENT, now U.S. Patent Application PublicationNo. 2011/0226837, which is hereby incorporated by reference in itsentirety. Additionally, U.S. patent application Ser. No. 12/893,461,filed Sep. 29, 2012, entitled STAPLE CARTRIDGE, now U.S. PatentApplication Publication No. 2012/0074198, is hereby incorporated byreference in its entirety. U.S. patent application Ser. No. 12/031,873,filed Feb. 15, 2008, entitled END EFFECTORS FOR A SURGICAL CUTTING ANDSTAPLING INSTRUMENT, now U.S. Pat. No. 7,980,443, is also herebyincorporated by reference in its entirety. The entire disclosure of U.S.Pat. No. 7,845,537, entitled SURGICAL INSTRUMENT HAVING RECORDINGCAPABILITIES, which issued on Dec. 7, 2010, is incorporated by referenceherein. The entire disclosure of U.S. application Ser. No. 13/118,241,entitled SURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENTARRANGEMENTS, now U.S. Patent Application Publication No. 2012/0298719,which was filed on May 27, 2011, is incorporated by reference herein.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, the device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicecan be disassembled, and any number of the particular pieces or parts ofthe device can be selectively replaced or removed in any combination.Upon cleaning and/or replacement of particular parts, the device can bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Thoseskilled in the art will appreciate that reconditioning of a device canutilize a variety of techniques for disassembly, cleaning/replacement,and reassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present application.

Preferably, the invention described herein will be processed beforesurgery. First, a new or used instrument is obtained and if necessarycleaned. The instrument can then be sterilized. In one sterilizationtechnique, the instrument is placed in a closed and sealed container,such as a plastic or TYVEK bag. The container and instrument are thenplaced in a field of radiation that can penetrate the container, such asgamma radiation, x-rays, or high-energy electrons. The radiation killsbacteria on the instrument and in the container. The sterilizedinstrument can then be stored in the sterile container. The sealedcontainer keeps the instrument sterile until it is opened in the medicalfacility.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

While this invention has been described as having exemplary designs, thepresent invention may be further modified within the spirit and scope ofthe disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

What is claimed is:
 1. A method for changing the spring rate of a tissuethickness compensator for use with a surgical instrument, said methodcomprising the steps of: obtaining a tissue thickness compensatorcomprising a first spring rate, wherein said tissue thicknesscompensator is at least partially comprised of a material having a glasstransition temperature and a melting temperature; heating said tissuethickness compensator to a temperature higher than said glass transitiontemperature and lower than said melting temperature; deforming saidtissue thickness compensator to induce a localized change in atissue-facing portion of said tissue thickness compensator from saidfirst spring rate to a second spring rate, wherein said second springrate is different than said first spring rate; allowing said tissuethickness compensator to cool below said glass transition temperature;and releasing said tissue thickness compensator.
 2. The method of claim1, wherein obtaining said tissue thickness compensator comprises thesteps of: obtaining a biocompatible polymer comprising a glasstransition temperature and a melting temperature; dissolving saidbiocompatible polymer in a solvent to produce a solution; andlyophilizing said solution.
 3. The method of claim 1, wherein the stepof deforming said tissue thickness compensator comprises holding atleast a portion of said tissue thickness compensator in a constrainedgeometry.
 4. The method of claim 1, wherein the step of deforming saidtissue thickness compensator comprises holding at least a portion ofsaid tissue thickness compensator under compression.
 5. The method ofclaim 1, further comprising the step of actively cooling said tissuethickness compensator to a temperature below said glass transitiontemperature.
 6. A method for changing the spring rate of a biocompatiblefoam for use with a surgical instrument, said method comprising thesteps of: obtaining a biocompatible foam comprising an original density,wherein said biocompatible foam is at least partially comprised of amaterial having a glass transition temperature and a meltingtemperature; heating said biocompatible foam to a temperature higherthan said glass transition temperature and lower than said meltingtemperature; manipulating a tissue-facing portion of said biocompatiblefoam to provide a localized change from said original density to amodified density, wherein said biocompatible foam which is not subjectto manipulation retains said original density; allowing saidbiocompatible foam to cool below said glass transition temperature; andreleasing said tissue-facing portion of said biocompatible foam.
 7. Themethod of claim 6, wherein the step of manipulating said tissue-facingportion of said biocompatible foam comprises applying at least onetensile force to said tissue-facing portion of said biocompatible foam.8. The method of claim 6, wherein the step of manipulating saidtissue-facing portion of said biocompatible foam comprises holding saidtissue-facing portion of said-biocompatible foam under compression. 9.The method of claim 6, wherein the step of manipulating saidtissue-facing portion of said biocompatible foam comprises holding saidtissue-facing portion of said biocompatible foam in a compressedgeometry.
 10. The method of claim 6, further comprising actively coolingsaid biocompatible foam to a temperature below said glass transitiontemperature.
 11. The method of claim 6, wherein the step of manipulatingsaid tissue-facing portion of said biocompatible foam comprisespositioning said biocompatible foam in a receiver and advancing anadjustment member against said tissue-facing portion of saidbiocompatible foam.
 12. A method for changing the spring rate of atissue thickness compensator for use with a surgical instrument, saidmethod comprising the steps of: obtaining a tissue thickness compensatorcomprising an original spring rate; transitioning a tissue-facingportion of said tissue thickness compensator from a non-glassy state toa glassy state; applying a force to said portion to induce a localizedchange from said original spring rate to a modified spring rate, whereinsaid tissue thickness compensator which is not subject to said forceretains said original spring rate; allowing said portion to return tosaid non-glassy state; and removing said force.
 13. The method of claim12, wherein said force comprises at least one compressive force.
 14. Themethod of claim 12, wherein said force comprises at least one tensileforce.
 15. The method of claim 12, further comprising actively coolingsaid tissue thickness compensator to a temperature below a glasstransition temperature.
 16. The method of claim 1, wherein said secondspring rate is greater than said first spring rate, wherein said secondspring rate corresponds to said tissue-facing portion of said tissuethickness compensator, and wherein said localized change increases thedensity of said tissue-facing portion of said tissue thicknesscompensator.
 17. The method of claim 6, wherein said modified density isgreater than said original density.
 18. The method of claim 12, whereinsaid modified spring rate is greater than said original spring rate,wherein said modified spring rate corresponds to said tissue-facingportion of said tissue thickness compensator, and wherein said localizedchange increases the density of said tissue-facing portion of saidtissue thickness compensator.